pri·ma·ry / ˈprīˌmerē; ˈprīm(ə)rē/ • adj. 1. of chief importance; principal: the government's primary aim is to see significant reductions in unemployment.2. earliest in time or order of development: the country was in the primary stage of socialism. ∎ not derived from, caused by, or based on anything else: the research involved the use of primary source materials in national and local archives.3. of or relating to education for children between the ages of about five and ten: a primary school.4. Biol. & Med. belonging to or directly derived from the first stage of development or growth: a primary bone tumor.5. (Primary) Geol. former term for Paleozoic.6. relating to or denoting the input side of a device using electromagnetic induction, esp. in a transformer.7. Chem. (of an organic compound) having its functional group located on a carbon atom that is bonded to no more than one other carbon atom. ∎ (chiefly of amines) derived from ammonia by replacement of one hydrogen atom by an organic group.• n. (pl. -ries) 1. (also primary election) a preliminary election to appoint delegates to a party conference or to select the candidates for a principal, esp. presidential, election.2. short for: ∎ a primary color. ∎ Ornithol. a primary feather. ∎ a primary coil or winding in an electrical transformer.3. Astron. the body orbited by a smaller satellite or companion.4. (the Primary) dated Geol. the Primary or Paleozoic era.