And to complete things, generic non-dc meta data that uses the meta tag with only a property attribute (no refines) is sometimes referred to as a primary meta tag. For example:
Code:
<meta property="createdwith">Sigil 0.9.17</meta>
which is used in place of the epub2 style meta tag
<meta name="createdwith" content="Sigil 0.9.17" />