Primary  —adj. 1 a of the first importance; chief. B fundamental, basic. 2 earliest, original; first in a series. 3 of the first rank in a series; not derived. 4 designating any of the colours red, green, and blue, or (for pigments) red, blue, and yellow, of which all other colours are mixtures. 5 (of education) for children below the age of 11. 6 (primary) geol. Of the lowest series of strata. 7 biol. Of the first stage of development. —n. (pl. -ies) 1 thing that is primary. 2 (in full primary election) (in the us) preliminary election to appoint party conference delegates or to select candidates for a principal (esp. Presidential) election. 3 = *primary feather.  primarily adv. [latin: related to *prime1]