adjective

1. first in time or order of development; primitive; original; earliest
2. from which others are derived; fundamental; elemental; basic
3. designating colors regarded as basic, or as those from which all others may be derived: classification of colors as primary varies
4. of or in the first stage of a sequence; elementary primary school
5. first in importance; chief; principal; main a primary concern
6. firsthand; direct a primary source of information
7. Chem.
   1. characterized by or resulting from the replacement of one atom or radical
   2. characterized by groups or radicals that are attached to the end carbon atom of a chain, i.e., to a CH group (Ex.: primary alcohols, CHOH; primary amines, CHNH)
8. Elec. designating or of an inducing current, input circuit, or input coil in a transformer, induction coil, etc.
9. Geol.
   1. formed directly by sedimentation, solidification, or precipitation and not subsequently altered: said of rocks
   2. Obsolete designating or of the earliest geological periods, up through the Paleozoic Era
10. Linguis. having as its fundamental form a base or other element that cannot be broken down: said of derivation
11. Med. designating or having to do with the initial medical care given to a patient, before referral to another doctor, a specialist, etc.
12. Zool. designating or of the large, stiff feathers on the last section, or hand, of a bird's wing

Etymology: ME prymary < L primarius < primus, first: see prime

noun pl. primaries -·ries

1. something first in order, quality, importance, etc.
2. ☆ in the U.S.,
   1. a local meeting of voters of a given political party to nominate candidates for public office, select delegates to a convention, etc.
   2. direct primary election
3. any of the primary colors
4. Astron.
   1. a sun, planet, etc. in relation to its satellites
   2. the brighter member of a binary star
5. Elec. a primary coil
6. Zool. a primary feather