tertiary

Third in place, order, degree, or rank.

Of, relating to, or designating the short flight feathers nearest the body on the rear edge of a bird’s wing.

Of, relating to, or having a carbon atom that is attached to three other carbon atoms in a molecule.

Of or relating to the replacement of three of several atoms or groups in a compound, such as an amine in which three valences of the functional group are taken by carbon atoms.

Of or relating to salts of acids containing three replaceable hydrogen atoms.

Of, relating to, or being the period of geologic time from about 65 to about 1.8 million years ago, the older of the two periods of the Cenozoic Era. The Tertiary Period is characterized by the appearance of modern flora, insects, fish, amphibians, and reptiles, and by the dominance of mammals as vertebrate life forms on land.

A tertiary feather.

The Tertiary Period.

A member of a religious Third Order.