terˈtiary /-shər-i/ adjective

1. Of the third degree, order or formation
2. Tertial (ornithology)
3. (with cap) of or belonging to the earlier period of the Cenozoic era, between 65 and 1.8 million years ago (geology)
4. Ranking above secondary (esp of education)
5. (of an industry) providing services rather than production or extraction

1. The Tertiary period
2. (without cap) a member of a third order of a monastic order, a layman who may continue to live an ordinary life in the world
3. A tertiary feather
4. That which is tertiary

tertiary amines plural noun (chem)

Amines in which the nitrogen atom is attached to three groups

tertiary college noun

A college, esp one with vocational courses, for the teaching of sixth-form-level students

tertiary colours plural noun

Colours resulting from the mixing of two secondary colours, eg olive produced by mixing orange and green