Tertiary (disambiguation)

The Tertiary is a geologic period.

Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may also refer to:
 * Tertiary (chemistry), a term describing bonding patterns in organic chemistry
 * In biochemistry, the tertiary structure of a protein is its overall shape, also known as its fold
 * Tertiary consumer, in ecology
 * Tertiary feathers or tertials, feathers attached to humerus or inner portion of the wings of birds
 * Tertiary color, a color made up by mixing one primary color with one secondary color, in a given color space
 * Tertiary sector of the economy, or the service sector
 * Tertiary education, educational levels following the completion of secondary education such as university or trade school
 * Tertiary care, specialized consultative healthcare
 * Tertiary, a member of a third order religious group
 * Tertiary source, in research
 * Tertiary stress, a proposed level of stress in phonetics