Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to: *

Tertiary period The Tertiary ( ) is an obsolete Period (geology), geologic period spanning 66 million to 2.6 or 1.8 million years ago. The period began with the extinction of the non-bird, avian dinosaurs in the Cretaceous–Paleogene extinction event, at t ...

, an obsolete geologic period spanning from 66 to 2.6 million years ago *

Tertiary (chemistry) Tertiary is a term used in organic chemistry to classify various types of compounds (e. g. alcohols, alkyl halides, amines) or reactive intermediates (e. g. alkyl radicals, carbocations). See also * Primary (chemistry) Primary is a term u ...

, a term describing bonding patterns in organic chemistry *

Tertiary care Health care, or healthcare, is the improvement or maintenance of health via the prevention, diagnosis, treatment, amelioration or cure of disease, illness, injury, and other physical and mental impairments in people. Health care is delive ...

, specialized consultative healthcare *

Tertiary color A secondary color is a color made by mixing two primary colors of a given color model in even proportions. Combining two secondary colors in the same manner produces a tertiary color. Secondary colors are special in traditional color theory, ...

, a color made up by mixing one primary color with one secondary color, in a given color space * Tertiary consumer, in ecology *

Tertiary education Tertiary education (higher education, or post-secondary education) is the educational level following the completion of secondary education. The World Bank defines tertiary education as including universities, colleges, and vocational schools ...

, educational levels following the completion of secondary education such as university or trade school * Tertiary feathers or tertials, feathers attached to humerus or inner portion of the wings of birds *

Tertiary sector of the economy The tertiary sector of the economy, generally known as the service sector, is the third of the three economic sectors in the three-sector model (also known as the economic cycle). The others are the primary sector (raw materials) and the seco ...

, or the service sector *

Tertiary source A tertiary source is an index or textual consolidation of already published primary and secondary sourcesTertiary stress, a proposed level of stress in phonetics * In biochemistry, the

tertiary structure Protein tertiary structure is the three-dimensional shape of a protein. The tertiary structure will have a single polypeptide chain "backbone" with one or more protein secondary structures, the protein domains. Amino acid side chains and the ...

of a protein is its overall shape, also known as its fold * Tertiary, a member of a

third order The term third order signifies, in general, lay members of Christian religious orders, who do not necessarily live in a religious community such as a monastery or a nunnery, and yet can claim to wear the religious habit and participate in the goo ...

religious group