tertiary

Any item considered to be of third order.

A tertiary colour.

Something from the Tertiary Period (the former term for the geologic period from 65 million to 2.58 million years ago).

A tertiary feather; a tertial.

A member of a Roman Catholic third order; a layperson who participates in activities similar to those engaged in by men and women who take religious vows (respectively the first and second orders), and who may wear some elements of an order's habit such as a scapular.

Of third rank or order; subsequent.

Possessing some quality in the third degree; especially having been subjected to the substitution of three atoms or radicals.

“a tertiary alcohol, amine, or salt”

Of quills: growing on the innermost joint of a bird's wing; tertial.