Oca
O´ca, n. [Sp.] (Bot.) A Peruvian name for certain species of Oxalis ( O. crenata, and O. tuberosa) which bear edible tubers.

Ocarina
Oc•a•ri´na, n. [Cf. It. carino pretty.] (Mus.) A kind of small simple wind instrument.

Occamy
Oc´ca•my, n. [A corruption of alchemy.] An alloy imitating gold or silver. [Written also ochimy, ochymy, etc.]

Occasion
Oc•ca´sion (ok•ka"zhun), n. [F. occasion, L. occasio, fr. occidere, occasum, to fall down; ob (see Ob- ) + cadere to fall. See Chance, and cf. Occident.]
1. A falling out, happening, or coming to pass; hence, that which falls out or happens; occurrence; incident.
"The unlooked-for incidents of family history, and its hidden excitements, and its arduous occasions." I. Taylor.
2. A favorable opportunity; a convenient or timely chance; convenience.
"Sin, taking occasion by the commandment, deceived me." Rom. vii. 11.
"I’ll take the occasion which he gives to bring Him to his death." Waller.
3. An occurrence or condition of affairs which brings with it some unlooked-for event; that which incidentally brings to pass an event, without being its efficient cause or sufficient reason; accidental or incidental cause.
"Her beauty was the occasion of the war." Dryden.
4. Need; exigency; requirement; necessity; as I have no occasion for firearms.
"After we have served ourselves and our own occasions." Jer. Taylor.
"When my occasions took me into France." Burke.
5. A reason or excuse; a motive; a persuasion.
"Whose manner was all passengers to stay, And entertain with her occasions sly." Spenser. On occasion, in case of need; in necessity; as convenience requires; occasionally. "That we might have intelligence from him on occasion," De Foe.
Syn. — Need; incident; use. See Opportunity.

Occasion
Oc•ca´sion (ok•ka"zhun), v. t. [ imp. & p. p. Occasioned (- zhund); p. pr. & vb. n. Occasioning.] [Cf.F. occasionner.] To give occasion to; to cause; to produce; to induce; as to occasion anxiety. South.
"If we inquire what it is that occasions men to make several combinations of simple ideas into distinct modes." Locke.

Occasionable
Oc•ca´sion•a•ble, a. Capable of being occasioned or caused. Barrow.

Occasional
Oc•ca´sion•al, a. [Cf.F. occasionnel.]
1. Of or pertaining to an occasion or to occasions; occuring at times, but not constant, regular, or systematic; made or happening as opportunity requires or admits; casual; incidental; as occasional remarks, or efforts.
"The … occasional writing of the present times." Bagehot.
2. Produced by accident; as the occasional origin of a thing. [Obs.] Sir T. Browne.Occasional cause (Metaph.), some circumstance preceding an effect which, without being the real cause, becomes the occasion of the action of the efficient cause; thus, the act of touching gunpowder with fire is the occasional, but not the efficient, cause of an explosion.

Occasionalism
Oc•ca´sion•al•ism, n. (Metaph.) The system of occasional causes; — a name given to certain theories of the Cartesian school of philosophers, as to the intervention of the First Cause, by which they account for the apparent reciprocal action of the soul and the body.

Occasionality
Oc•ca•sion•al´i•ty, n. Quality or state of being occasional; occasional occurrence. [R.]

Occasionally
Oc•ca´sion•al•ly, adv. In an occasional manner; on occasion; at times, as convenience requires or opportunity offers; not regularly. Stewart.
"The one, Wolsey, directly his subject by birth; the other, his subject occasionally by his preferment." Fuller.

Occasionate
Oc•ca´sion•ate, v. t. To occasion. [Obs.]
"The lowest may occasionate much ill." Dr. H. More.

Occasioner
Oc•ca´sion•er, n. One who, or that which, occasions, causes, or produces. Bp. Sanderson.

Occasive
Oc•ca´sive, a. [L. occasivus, fr. occasus a going down, setting of the heavenly bodies, fr. occidere to fall or down. See Occasion.] Of or pertaining to the setting sun; falling; descending; western.

Occecation
Oc•ce•ca´tion, n. [L. occaecatio, fr. occaecare to make blind; ob + caecare to blind, fr. caecus blind.] The act of making blind, or the state of being blind. [R.] "This inward occecation." Bp. Hall.

Occident
Oc´ci•dent, n. [F., fr. L. occidens, occidentis, fr. occidents, p. pr. of occidere to fall or go down. See Occasion.] The part of the horizon where the sun last appears in the evening; that part of the earth towards the sunset; the west; — opposed to orient. Specifically, in former times, Europe as opposed to Asia; now, also the Western hemisphere. Chaucer.
"I may wander from east to occident." Shak.

Occidental
Oc•ci•den´tal, a. [L. occidentalis; cf. F. occidental.]
1. Of, pertaining to, or situated in, the occident, or west; western; — opposed to oriental; as occidental climates, or customs; an occidental planet.
2. Possessing inferior hardness, brilliancy, or beauty; — used of inferior precious stones and gems, because those found in the Orient are generally superior.

Occidentals
Oc•ci•den´tals, n. pl. (Eccl.) Western Christians of the Latin rite. See Orientals. Shipley.

Occiduous
Oc•cid´u•ous, a. [L. occiduus, fr. occidere to go down.] Western; occidental. [R.] Blount.

Occipital
Oc•cip´i•tal, a. [Cf. F. occipital.] (Anat.) Of or pertaining to the occiput, or back part of the head, or to the occipital bone. Occipital bone (Anat.), the bone which forms the posterior segment of the skull and surrounds the great foramen by which the spinal cord leaves the cranium. In the higher vertebrates it is usually composed of four bones, which become consolidated in the adult. — Occipital point (Anat.), the point of the occiput in the mesial plane farthest from the ophryon.

Occipital
Oc•cip´i•tal, n. (Anat.) The occipital bone.

Occipito-
Oc•cip´i•to- . [See Occiput.] A combining form denoting relation to, or situation near, the occiput; as occipito-axial; occipito- mastoid.

Occipitoaxial
Oc•cip•i•to•ax´i•al, a. (Anat.) Of or pertaining to the occipital bone and second vertebra, or axis.

Occiput
Oc´ci•put, n. ; pl. L. Occipita (#), E. Occiputs. [L., fr. ob (see Ob-) + caput head. See Chief.]
1. (Anat.) The back, or posterior, part of the head or skull; the region of the occipital bone.
2. (Zoöl.) A plate which forms the back part of the head of insects.

Occision
Oc•ci´sion, n. [L. occisio, fr. occidere, occisium, to cut down, to kill; ob (see Ob-) + caedere to cut.] A killing; the act of killing. [Obs.] Sir M. Hale.

Occlude
Oc•clude´, v. t. [L. occludere, occlusum; ob (see Ob-) + claudere to shut.]
1. To shut up; to close. Sir T. Browne.
2. (Chem.) To take in and retain; to absorb; — said especially with respect to gases; as iron, platinum, and palladium occlude large volumes of hydrogen.

Occludent
Oc•clud´ent, a. [L. occludens, p. pr. of occludere.] Serving to close; shutting up. — n. That which closes or shuts up. Sterne.

Occluse
Oc•cluse´, a. [L. occlusus, p. p. See Occlude.] Shut; closed. [Obs.] Holder.

Occlusion
Oc•clu´sion, n. [See Occlude.]
1. The act of occluding, or the state of being occluded.
"Constriction and occlusion of the orifice." Howell.
2. (Med.) The transient approximation of the edges of a natural opening; imperforation. Dunglison. Occlusion of gases (Chem. & Physics), the phenomenon of absorbing gases, as exhibited by platinum, palladium, iron, or charcoal; thus, palladium absorbs, or occludes, nearly a thousand times its own volume of hydrogen, and in this case a chemical compound seems to be formed.

Occrustate
Oc•crus´tate, v. t. [See Ob-, and Crustated.] To incrust; to harden. [Obs.] Dr. H. More.

Occult
Oc•cult´, a. [L. occultus, p. p. of occulere to cover up, hide; ob (see Ob- ) + a root prob.akin to E. hell: cf. F. occulte.] Hidden from the eye or the understanding; inviable; secret; concealed; unknown.
"It is of an occult kind, and is so insensible in its advances as to escape observation." I. Taylor.Occult line (Geom.), a line drawn as a part of the construction of a figure or problem, but not to appear in the finished plan. — Occult qualities, those qualities whose effects only were observed, but the nature and relations of whose productive agencies were undetermined; — so called by the schoolmen. — Occult sciences, those sciences of the Middle Ages which related to the supposed action or influence of occult qualities, or supernatural powers, as alchemy, magic, necromancy, and astrology.

Occult
Oc•cult´, v. t. To eclipse; to hide from sight.

Occultation
Oc•cul•ta´tion, n. [L. occultatio a hiding, fr. occultare, v. intens. of occulere: cf.F. occultation. See Occult.]
1. (Astron.) The hiding of a heavenly body from sight by the intervention of some other of the heavenly bodies; — applied especially to eclipses of stars and planets by the moon, and to the eclipses of satellites of planets by their primaries.
2. Fig.: The state of being occult.
"The reappearance of such an author after those long periods of occultation." Jeffrey. Circle of perpetual occultation. See under Circle.

Occulted
Oc•cult´ed, a.
1. Hidden; secret. [Obs.] Shak.
2. (Astron.) Concealed by the intervention of some other heavenly body, as a star by the moon.

Occulting
Oc•cult´ing, n. Same as Occultation.

Occultism
Oc•cult´ism, n. A certain Oriental system of theosophy. A. P. Sinnett.

Occultist
Oc•cult´ist, n. An adherent of occultism.

Occultly
Oc•cult´ly, adv. In an occult manner.

Occultness
Oc•cult´ness, n. State or quality of being occult.

Occupancy
Oc´cu•pan•cy, n. [See Occupant.] The act of taking or holding possession; possession; occupation. Title by occupancy (Law), a right of property acquired by taking the first possession of a thing, or possession of a thing which belonged to nobody, and appropriating it. Blackstone. Kent.

Occupant
Oc´cu•pant, n. [L. occupans, p. pr. of occupare: cf. F. occupant. See Occupy.]
1. One who occupies, or takes possession; one who has the actual use or possession, or is in possession, of a thing. This word, in law, sometimes signifies one who takes the first possession of a thing that has no owner.
2. A prostitute. [Obs.] Marston.

Occupate
Oc´cu•pate, v. t. [L. occupatus, p. p. of occupare. See Occupy.] To occupy. [Obs.] Bacon.

Occupation
Oc•cu•pa´tion, n. [L. occupatio: cf.F. occupation.]
1. The act or process of occupying or taking possession; actual possession and control; the state of being occupied; a holding or keeping; tenure; use; as the occupation of lands by a tenant.
2. That which occupies or engages the time and attention; the principal business of one’s life; vocation; employment; calling; trade.
"Absence of occupation is not rest." Cowper. Occupation bridge (Engin.), a bridge connecting the parts of an estate separated by a railroad, a canal, or an ordinary road.
Syn. — Occupancy; possession; tenure; use; employment; avocation; engagement; vocation; calling; office; trade; profession.

Occupier
Oc´cu•pi•er, n.
1. One who occupies, or has possession.
2. One who follows an employment; hence, a tradesman. [Obs.] "Merchants and occupiers." Holland.
"The occupiers of thy merchandise." Ezek. xxvii. 27.

Occupy
Oc´cu•py, v. t. [ imp. & p. p. Occupied p. pr. & vb. n. Occupying ] [OE. occupien, F. occuper, fr.L. occupare; ob (see Ob-) + a word akin to capere to take. See Capacious.]
1. To take or hold possession of; to hold or keep for use; to possess.
"Woe occupieth the fine [/end] of our gladness." Chaucer.
"The better apartments were already occupied." W. Irving.
2. To hold, or fill, the dimensions of; to take up the room or space of; to cover or fill; as the camp occupies five acres of ground. Sir J. Herschel.
3. To possess or use the time or capacity of; to engage the service of; to employ; to busy.
"An archbishop may have cause to occupy more chaplains than six." Eng. Statute (Hen. VIII. )
"They occupied themselves about the Sabbath." 2 Macc. viii. 27.
4. To do business in; to busy one’s self with. [Obs.]
"All the ships of the sea, with their mariners, were in thee to occupy the merchandise." Ezek. xxvii. 9.
"Not able to occupy their old crafts." Robynson (More’s Utopia).
5. To use; to expend; to make use of. [Obs.]
"All the gold that was occupied for the work." Ex. xxxviii. 24.
"They occupy not money themselves." Robynson (More’s Utopia).
6. To have sexual intercourse with. [Obs.] Nares.

Occupy
Oc´cu•py, v. i.
1. To hold possession; to be an occupant. "Occupy till I come." Luke xix. 13.
2. To follow business; to traffic.

Occur
Oc•cur´, v. i. [ imp. & p. p. Occurred p. pr. & vb. n. Occurring ] [L. occurrere, occursum; ob (see Ob-) + currere to run. See Course.]
1. To meet; to clash. [Obs.]
"The resistance of the bodies they occur with." Bentley.
2. To go in order to meet; to make reply. [Obs.]
"I must occur to one specious objection." Bentley.
3. To meet one’s eye; to be found or met with; to present itself; to offer; to appear; to happen; to take place; as I will write if opportunity occurs.
"In Scripture, though the word heir occur, yet there is no such thing as "heir" in our author’s sense." Locke.
4. To meet or come to the mind; to suggest itself; to be presented to the imagination or memory.
"There doth not occur to me any use of this experiment for profit." Bacon.

Occurrence
Oc•cur´rence, n. [Cf. F. occurrence. See Occur.]
1. A coming or happening; as the occurence of a railway collision.
"Voyages detain the mind by the perpetual occurrence and expectation of something new." I. Watts.
2. Any incident or event; esp., one which happens without being designed or expected; as an unusual occurrence, or the ordinary occurrences of life.
"All the occurrence of my fortune." Shak.
Syn. — See Event.

Occurrent
Oc•cur´rent, a. [L. occurrens, -entis, p. pr. of occurrere: cf.F. occurrent. See Occur.] Occurring or happening; hence, incidental; accidental.

Occurrent
Oc•cur´rent, n.
1. One who meets; hence, an adversary. [Obs.] Holland.
2. Anything that happens; an occurrence. [Obs.]
"These we must meet with in obvious occurrents of the world." Sir T. Browne.

Occurse
Oc•curse´, n. [L. occursus.] Same as Occursion. [Obs.] Bentley.

Occursion
Oc•cur´sion, n. [L. occursio. See Occur.] A meeting; a clash; a collision. [Obs.] Boyle.

Ocean
O´cean (o"sh an), n. [F. ocean, L. oceanus, Gr. ’wkeano•s ocean, in Homer, the great river supposed to encompass the earth.]
1. The whole body of salt water which covers more than three fifths of the surface of the globe; — called also the sea, or great sea.
"Like the odor of brine from the ocean Comes the thought of other years." Longfellow.
2. One of the large bodies of water into which the great ocean is regarded as divided, as the Atlantic, Pacific, Indian, Arctic and Antarctic oceans.
3. An immense expanse; any vast space or quantity without apparent limits; as the boundless ocean of eternity; an ocean of affairs. Locke.

Ocean
O´cean (o"sh an), a. Of or pertaining to the main or great sea; as the ocean waves; an ocean stream. Milton.

Oceanic
O•ce•an´ic, a. [Cf.F. oceanique. See Ocean.]
1. Of or pertaining to the ocean; found or formed in or about, or produced by, the ocean; frequenting the ocean, especially mid- ocean.
"Petrels are the most aërial and oceanic of birds." Darwin.
2. Of or pertaining to Oceania or its inhabitants.

Oceanography
O•cean•og´ra•phy, n. [ Ocean + -graphy.] A description of the ocean.

Oceanology
O•cean•ol´o•gy, n. [ Ocean + -logy.] That branch of science which relates to the ocean.

Oceanus
O•ce´a•nus, n. [L., from Gr. .] (Gr.Myth.) The god of the great outer sea, or the river which was believed to flow around the whole earth.

Ocellary
O•cel´la•ry, a. Of or pertaining to ocelli.

Ocellate
O•cel´late, a. Same as Ocellated.

Ocellated
O•cel´la•ted, a. [L. ocellatus, fr. ocellus a little eye, dim. of oculus an eye.]
1. Resembling an eye.
2. Marked with eyelike spots of color; as the ocellated blenny. Ocellated turkey (Zoöl.), the wild turkey of Central America ( Meleagris ocellata).

Ocellus
O•cel´lus, n. ; pl. Ocelli (#). [L., dim. of oculus an eye.] (Zoöl.) (a) A little eye; a minute simple eye found in many invertebrates. (b) An eyelike spot of color, as those on the tail of the peacock.

Oceloid
O´ce•loid, a. [ Ocelot + - oid.] (Zoöl.) Resembling the ocelot.

Ocelot
O´ce•lot, n. [Mexican ocelotl.] (Zoöl.) An American feline carnivore ( Felis pardalis). It ranges from the Southwestern United States to Patagonia. It is covered with blackish ocellated spots and blotches, which are variously arranged. The ground color varies from reddish gray to tawny yellow. { O´cher, O´chre }, n. [F. ocre, L. ochra, fr. Gr., from pale, pale yellow.] (Min.) (a) A impure earthy ore of iron or a ferruginous clay, usually red (hematite) or yellow (limonite), — used as a pigment in making paints, etc. The name is also applied to clays of other colors. (b) A metallic oxide occurring in earthy form; as tungstic ocher or tungstite. { O´cher•ous, O´chre•ous }, a. [Cf. F. ocreux.] Of or pertaining to ocher; containing or resembling ocher; as ocherous matter; ocherous soil.

Ochery
O´cher•y, a. Ocherous. [Written also ochrey, ochry.]

Ochimy
Och•i•my, n. [Obs.] See Occamy.

Ochlesis
Och•le´sis, n. [NL., fr. Gr. disturbance, fr. crowd, mob.] (Med.) A general morbid condition induced by the crowding together of many persons, esp. sick persons, under one roof. G. Gregory.

Ochlocracy
Och•loc´ra•cy, n. [Gr. ; the populace, multitude + to be strong, to rule, strength: cf.F. ochlocratie.] A form of government by the multitude; a mobocracy. Hare. { Och•lo•crat•ic, Och•lo•crat•ic•al } a. Of or pertaining to ochlocracy; having the form or character of an ochlocracy; mobocratic. — Och•lo•crat´ic•al•ly, adv.

Ochraceous
O•chra´ceous, a. Ocherous.

Ochre
O´chre, n. (Min.) See Ocher.

Ochrea
O´chre•a, n. ; pl. Ochreaee (#). [L.]
1. (Antiq.) A greave or legging.
2. (Bot.) A kind of sheath formed by two stipules united round a stem. { O´chre•ate, O´chre•a•ted } a.
1. Wearing or furnished with an ochrea or legging; wearing boots; booted.
"A scholar undertook … to address himself ochreated unto the vice chancellor." Fuller.
2. (Bot.) Provided with ochrea, or sheathformed stipules, as the rhubarb, yellow dock, and knotgrass.

Ochreous
O´chre•ous, a. See Ocherous.

Ochrey
O´chrey, a. See Ochery.

Ochroleucous
Och•ro•leu´cous, a. [Gr. ocher + white.] Yellowish white; having a faint tint of dingy yellow. Gray.

Ochry
O´chry, a. See Ochery.

Ochymy
Och´y•my, n. [Obs.] See Occamy.

Ocra
O´cra, n. (Bot.) See Okra.

Ocrea
O´cre•a, n. [L.] See Ochrea. { O´cre•ate, O´cre•a´ted } a. [See Ochrea.] Same as Ochreate, Ochreated.

Octa-
Oc´ta- A prefix meaning eight. See Octo-.

Octachord
Oc´ta•chord, n. [Gr. with eight strings; (for eight) + string, chord: cf.F. octacorde.] (Mus.) An instrument of eight strings; a system of eight tones. [Also written octochord.]

Octad
Oc´tad, n. [Gr.,, the number eight.] (Chem.) An atom or radical which has a valence of eight, or is octavalent.

Octaedral
Oc•ta•e´dral, a. See Octahedral.

Octaemeron
Oc•ta•em´e•ron, n. [NL., fr. Gr., neut. of of the eighth day.] (Eccl.) A fast of eight days before a great festival. Shipley.

Octagon
Oc´ta•gon, n. [Gr. eight- cornered; (for eight) + an angle: cf.F. cctogone.]
1. (Geom.) A plane figure of eight sides and eight angles.
2. Any structure (as a fortification) or place with eight sides or angles. Regular octagon, one in which the sides are all equal, and the angles also are all equal.

Octagonal
Oc•tag´o•nal, a. Having eight sides and eight angles.

Octagynous
Oc•tag´y•nous, a. [ Octa- + Gr. wife.] (Bot.) Having eight pistils or styles; octogynous.

Octahedral
Oc•ta•he´dral, a. [See Octahedron.] Having eight faces or sides; of, pertaining to, or formed in, octahedrons; as octahedral cleavage. Octahedral borax (Chem.), borax obtained from a saturated solution in octahedral crystals, which contain five molecules of water of crystallization; distinguished from common or prismatic borax. — Octahedral iron ore (Min.), magnetite.

Octahedrite
Oc•ta•he´drite, n. (Min.) Titanium dioxide occurring in acute octahedral crystals.

Octahedron
Oc•ta•he´dron, n. [Gr., fr. eight-side; (for eight) + seat, base, from to sit.] (Geom.) A solid bounded by eight faces. The regular octahedron is contained by eight equal equilateral triangles.

Octamerous
Oc•tam´er•ous, a. [ Octa- + Gr. part.] (Biol.) Having the parts in eights; as an octamerous flower; octamerous mesenteries in polyps.

Octander
Oc•tan´der, n. One of the Octandria.

Octandria
Oc•tan´dri•a, n. pl. [NL., fr. Gr. (for eight) +,, male, man.] (Bot.) A Linnaean class of plants, in which the flowers have eight stamens not united to one another or to the pistil. { Oc•tan´dri•an, Oc•tan´drous } a. (Bot.) Of or pertaining to the Octandria; having eight distinct stamens.

Octane
Oc´tane, n. [See Octa-] . (Chem.) Any one of a group of metametric hydrocarcons (C₈H₁₈) of the methane series. The most important is a colorless, volatile, inflammable liquid, found in petroleum, and a constituent of benzene or ligroin.

Octangular
Oc•tan´gu•lar, a. [L. octangulus eight-cornered; octo eight + angulus angle.] Having eight angles; eight-angled. — Oc•tan´gu•lar•ness, n.

Octant
Oc´tant, n. [L. octans, - antis. fr. octo eight. See Octave.]
1. (Geom.) The eighth part of a circle; an arc of 45 degrees.
2. (Astron. & Astrol.) The position or aspect of a heavenly body, as the moon or a planet, when half way between conjunction, or opposition, and quadrature, or distant from another body 45 degrees.
3. An instrument for measuring angles (generally called a quadrant), having an arc which measures up to 9O°, but being itself the eighth part of a circle. Cf. Sextant.
4. (Math. & Crystallog.) One of the eight parts into which a space is divided by three coördinate planes.

Octapla
Oc´ta•pla, n. ; etymol. pl. , but syntactically sing. [NL., fr.Gr. (for eight) + -pla, as in E. hexapla; cf.Gr. eightfold.] A portion of the Old Testament prepared by Origen in the 3d century, containing the Hebrew text and seven Greek versions of it, arranged in eight parallel columns.

Octaroon
Oc•ta•roon´, n. See Octoroon.

Octastyle
Oc´ta•style, a. See Octostyle.

Octateuch
Oc´ta•teuch, n. [L. octateuchus, Gr. .] A collection of eight books; especially, the first eight books of the Old Testament. [R.]

Octavalent
Oc•tav´a•lent, a. [ Octa- + L. valens, p. pr. See Valence.] (Chem.) Having a valence of eight; capable of being combined with, exchanged for, or compared with, eight atoms of hydrogen; — said of certain atoms or radicals.

Octave
Oc´tave, n. [F., fr. L. octava an eighth, fr. octavus eighth, fr. octo eight. See Eight, and cf. Octavo, Utas.]
1. The eighth day after a church festival, the festival day being included; also the week following a church festival. "The octaves of Easter." Jer. Taylor.
2. (Mus.) (a) The eighth tone in the scale; the interval between one and eight of the scale, or any interval of equal length; an interval of five tones and two semitones. (b) The whole diatonic scale itself. The ratio of a musical tone to its octave above is 1:2 as regards the number of vibrations producing the tones.
3. (Poet.) The first two stanzas of a sonnet, consisting of four verses each; a stanza of eight lines.
"With mournful melody it continued this octave." Sir P. Sidney.Double octave. (Mus.) See under Double. — Octave flute (Mus.), a small flute, the tones of which range an octave higher than those of the German or ordinary flute; — called also piccolo. See Piccolo.
4. A small cask of wine, the eighth part of a pipe.

Octave
Oc´tave, a. Consisting of eight; eight. Dryden.

Octavo
Oc•ta´vo, n. ; pl. Octavos (#). [L. in octavo; in in + octavo, abl. of octavus. See Octave.] A book composed of sheets each of which is folded into eight leaves; hence, indicating more or less definitely a size of book so made; — usually written 8vo or 8°.

Octavo
Oc•ta´vo, a. Having eight leaves to a sheet; as an octavo form, book, leaf, size, etc.

Octene
Oc´tene, n. [See Octo-.] (Chem.) Same as Octylene.

Octennial
Oc•ten´ni•al, a. [L. octennium a period of eight years; octo eight + annus year.] Happening every eighth year; also lasting a period of eight years. Johnson. — Oc•ten´ni•al•ly, adv.

Octet
Oc•tet´, n. [From L. octo eight, like E. duet, fr.L. duo. See Octave.] (Mus.) A composition for eight parts, usually for eight solo instruments or voices.

Octic
Oc´tic, a. [ Octo- + - ic.] (Math.) Of the eighth degree or order. — n. (Alg.) A quantic of the eighth degree.

Octile
Oc´tile, n. [Cf. F. octil, a. See Octant.] Same as Octant, 2. [R.]

Octillion
Oc•til´lion, n. [L. octo eight + -illion, as in E. million: cf. F. octillion.] According to the French method of numeration (which method is followed also in the United States) the number expressed by a unit with twenty-seven ciphers annexed. According to the English method, the number expressed by a unit with forty-eight ciphers annexed. See Numeration. { Oc´to-, Oc´ta- }. [L. octo eight, Gr., with a combining form . Cf. Eight.] A combining form meaning eight; as in octodecimal, octodecimal, octolocular.

Octoate
Oc´to•ate, n. (Chem.) A salt of an octoic acid; a caprylate.

October
Oc•to´ber, n. [L., the eighth month of the primitive Roman year, which began in March, fr. octo eight: cf.F. Octobre. See Octave.]
1. The tenth month of the year, containing thirty-one days.
2. Ale or cider made in that month.
"The country gentlemen had a posset or drink they called October." Emerson.

Octocera
Oc•toc´e•ra, n. pl. [NL.] Octocerata.

Octocerata
Oc•to•cer´a•ta, n. pl. [NL., fr. Gr. eight +, a horn.] (Zoöl.) A suborder of Cephalopoda including Octopus, Argonauta, and allied genera, having eight arms around the head; — called also Octopoda.

Octochord
Oc´to•chord, n. (Mus.) See Octachord.

Octodecimo
Oc•todec´i•mo, a. [L. octodecim eighteen. See Octavo, Decimal, and -mo.] Having eighteen leaves to a sheet; as an octodecimo form, book, leaf, size, etc.

Octodecimo
Oc•to•dec´i•mo, n. ; pl. Octodecimos . A book composed of sheets each of which is folded into eighteen leaves; hence; indicating more or less definitely a size of book, whose sheets are so folded; — usually written 18mo or 18°, and called eighteenmo.

Octodentate
Oc•to•den´tate, a. [ Octo- + dentate.] Having eight teeth.

Octodont
Oc´to•dont, a. [ Octo- + Gr., .] (Zoöl.) Of or pertaining to the Octodontidae, a family of rodents which includes the coypu, and many other South American species.

Octoedrical
Oc•to•ed´ric•al, a. See Octahedral. [Obs.] Sir T. Browne.

Octofid
Oc´to•fid, a. [ Octo- + root of L. findere to split: cf.F. octofide.] (Bot.) Cleft or separated into eight segments, as a calyx.

Octogamy
Oc•tog´a•my, n. [ Octo- + Gr. marriage.] A marrying eight times. [R.] Chaucer.

Octogenarian
Oc•to•ge•na´ri•an, n. A person eighty years, or more, of age.

Octogenary
Oc•tog´e•na•ry, a. [L. octogenarrus, from octogeni eighty each, octoginta eighty, fr. octo eight. See Eight, Eighty.] Of eighty years of age. "Being then octogenary." Aubrey.

Octogild
Oc´to•gild, n. [ Octo- + AS. gild payment.] (Anglo-Saxon Law) A pecuniary compensation for an injury, of eight times the value of the thing.

Octogonal
Oc•tog´o•nal, a. See Octagonal. [Obs.]

Octogynia
Oc•to•gyn´i•a, n. pl. [NL., from Gr. eight + a woman, female.] (Bot.) A Linnaean order of plants having eight pistils. { Oc•to•gyn´i•an, Oc•tog´y•nous } a. (Bot.) Having eight pistils; octagynous.

Octoic
Oc•to´ic, a. [See Octo-.] (Chem.) Pertaining to, derived from, or resembling, octane; — used specifically, to designate any one of a group of acids, the most important of which is called caprylic acid.

Octolocular
Oc•to•loc´u•lar, a. [ Octo- + locular.] (Bot.) Having eight cells for seeds.

Octonaphthene
Oc•to•naph´thene, n. [ Octo- + naphthene.] (Chem.) A colorless liquid hydrocarbon of the octylene series, occurring in Caucasian petroleum.

Octonary
Oc•to•na•ry, a. [L. octonarius, fr. octoni eight each, fr. octo eight.] Of or pertaining to the number eight. Dr. H. More.

Octonocular
Oc•to•noc´u•lar, a. [L. octoni eight each + E. ocular.] Having eight eyes. Derham.

Octopede
Oc•to•pede, n. [ Octo- + L. pes, pedis, foot.] (Zoöl.) An animal having eight feet, as a spider.

Octopetalous
Oc•to•pet´al•ous, a. [ Octo- + petal.] (Bot.) Having eight petals or flower leaves.

Octopod
Oc´to•pod, n. [Gr. eight- footed; eight + poy•s, podo•s, foot: cf.F. octopode.] (Zoöl.) One of the Octocerata.

Octopoda
Oc•top´o•da, n. pl. [NL.] (Zoöl.) (a) Same as Octocerata. (b) Same as Arachnida.

Octopodia
Oc•to•po´di•a, n. pl. [NL., fr. Gr. eight + a little foot.] (Zoöl.) Same as Octocerata.

Octopus
Oc´to•pus, n. [NL. See Octopod.] (Zoöl.) A genus of eight-armed cephalopods, including numerous species, some of them of large size. See Devilfish,

Octoradiated
Oc•to•ra´•di•a•ted, a. [ Octo- + radiated.] Having eight rays.

Octoroon
Oc•to•roon´, n. [L. octo eight + -roon, as in quadroon.] The offspring of a quadroon and a white person; a mestee.

Octospermous
Oc•to•sper´mous, a. [ Octo- + Cr. seed.] (Bot.) Containing eight seeds.

Octostichous
Oc•tos´ti•chous, a. [ Octo- + Gr. a row.] (Bot.) In eight vertical ranks, as leaves on a stem.

Octostyle
Oc´to•style, a. [ Octo- + Gr. a pillar: cf.F. octostyle.] (Arch.) Having eight columns in the front; — said of a temple or portico. The Parthenon is octostyle, but most large Greek temples are hexastele. See Hexastyle. — n. An octostyle portico or temple. { Oc•to•syl•lab´ic, Oc•to•syl•lab´ic•al, } a. [L. octosyllabus. See Octo-, and Syllable.] Consisting of or containing eight syllables.

Octosyllable
Oc´to•syl•la•ble, a. Octosyllabic.

Octosyllable
Oc´to•syl•la•ble, n. A word of eight syllables.

Octoyl
Oc´to•yl, n. [ Octoic + -yl.] (Chem.) A hypothetical radical (C₈H₁₅O), regarded as the essential residue of octoic acid.

Octroi
Oc•troi´, n. [F.]
1. A privilege granted by the sovereign authority, as the exclusive right of trade granted to a guild or society; a concession.
2. A tax levied in money or kind at the gate of a French city on articles brought within the walls. [Written also octroy.]

Octuor
Oc´tu•or, n. [From L. octo eight + -uor, as in L. quatuor.] (Mus.) See Octet. [R.]

Octuple
Oc´tu•ple, a. [L. octuplus; cf. Gr. : cf.F. octuple.] Eightfold.

Octyl
Oc´tyl, n. [ Octane + - yl.] (Chem.) A hypothetical hydrocarbon radical regarded as an essential residue of octane, and as entering into its derivatives; as octyl alcohol.

Octylene
Oc´tyl•ene, n. [ Octane + eth ylene.] (Chem.) Any one of a series of metameric hydrocarbons (C₈H₁₆) of the ethylene series. In general they are combustible, colorless liquids.

Octylic
Oc•tyl´ic, a. (Chem.) Pertaining to, derived from, or containing, octyl; as octylic ether.

Ocular
Oc´u•lar, a. [L. ocularis, ocularius, fr. oculus the eye: cf.F. oculaire. See Eye, and cf. Antler, Inveigle.]
1. Depending on, or perceived by, the eye; received by actual sight; personally seeing or having seen; as ocular proof. Shak.
"Thomas was an ocular witness of Christ’s death." South.
2. (Anat.) Of or pertaining to the eye; optic.

Ocular
Oc´u•lar, n. (Opt.) The eyepiece of an optical instrument, as of a telescope or microscope.

Ocularly
Oc´u•lar•ly, adv. By the eye, or by actual sight.

Oculary
Oc´u•la•ry, a. Of or pertaining to the eye; ocular; optic; as oculary medicines. Holland. { Oc´u•late, Oc´u•la•ted } a. [L. oculatus, fr. oculus eye.]
1. Furnished with eyes.
2. Having spots or holes resembling eyes; ocellated.

Oculiform
Oc•u•li•form, a. [L. oculus the eye + form: cf.F. oculiforme.] In the form of an eye; resembling an eye; as an oculiform pebble.

Oculina
Oc•u•li´na, n. [NL., fr. L. oculus the eye.] (Zoöl.) A genus of tropical corals, usually branched, and having a very volid texture.

Oculinacea
Oc•u•li•na´•ce•a, n. pl. [NL., fr. NL. oculina the name of a typical genus.] (Zoöl.) A suborder of corals including many reef- building species, having round, starlike calicles.

Oculist
Oc´u•list, n. [L. oculus the eye: cf. F. oculiste.] One skilled in treating diseases of the eye.

Oculo-
Oc´u•lo- A combining form from L. oculus the eye.

Oculomotor
Oc•u•lo•mo´tor, a. [ Oculo- + motor.] (Anat.) Of or pertaining to the movement of the eye; — applied especially to the common motor nerves (or third pair of cranial nerves) which supply many of the muscles of the orbit. — n. The oculomotor nerve.

Oculonasal
Oc•u•lo•na´sal, a. [ Oculo- + nasal.] (Anat.) Of or pertaining to the region of the eye and the nose; as the oculonasal, or nasal, nerve, one of the branches of the ophthalmic.

Oculus
Oc´u•lus, n. ; pl. Oculi (#). [L., an eye.]
1. An eye; (Bot.) a leaf bud.
2. (Arch.) A round window, usually a small one.

Ocypodian
O•cy•po´di•an, n. [Gr. ’wky•s swift + poy•s, podo•s, foot.] (Zoöl.) One of a tribe of crabs which live in holes in the sand along the seashore, and run very rapidly, — whence the name.