Œsophagus
Œ•soph"a•gus, n. , Œ•so•phag"e•al, a. , etc. Same as Esophagus, Esophageal, etc.

Œstrian
Œs"tri•an, a. (Zoöl.) Of or pertaining to the gadflies. — n. A gadfly.

Œstrual
Œs"tru•al, a. [See Œstrus.] (Physiol.) Of or pertaining to sexual desire; — mostly applied to brute animals; as the œstrual period; œstrual influence.

Œstruation
Œs•tru•a"tion, n. (Physiol.) The state of being under œstrual influence, or of having sexual desire.

Œstrus
Œs"trus, n. [L., a gadfly; also frenzy, fr.Gr. gadfly; hence, sting, fury, insane desire, frenzy.]
1. (Zoöl.) A genus of gadflies. The species which deposits its larvae in the nasal cavities of sheep is œstrus ovis.
2. A vehement desire; esp. (Physiol.), the periodical sexual impulse of animals; heat; rut.