primary (adj.)

early 15c., "of the first order," from Latin primarius "of the first rank, chief, principal, excellent," from primus "first" (see prime (adj.)). Meaning "first in order" is from 1802. Primary color is first recorded 1610s (at first the seven of the spectrum, later the three from which others can be made); primary school is 1802, from French école primaire.

The Paris journals ... are full of a plan, brought forward by Fourcroy, for the establishment of primary schools, which is not interesting to an English reader. [London Times, April 27, 1802]

Related: Primarily.

primary (n.)

1861, American English, short for primary election (1792, with reference to France; in a U.S. context from 1835); earlier primary caucus (1821).

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Definitions of primary from WordNet
primary (n.)
a preliminary election where delegates or nominees are chosen;
Synonyms: primary election
primary (n.)
one of the main flight feathers projecting along the outer edge of a bird's wing;
Synonyms: primary feather / primary quill
primary (n.)
(astronomy) a celestial body (especially a star) relative to other objects in orbit around it;
primary (n.)
coil forming the part of an electrical circuit such that changing current in it induces a current in a neighboring circuit;
current through the primary coil induces current in the secondary coil
Synonyms: primary coil / primary winding
primary (adj.)
most important element;
policemen were primary targets
Synonyms: chief / main / principal / master
primary (adj.)
of first rank or importance or value; direct and immediate rather than secondary;
a primary effect
primary sources
primary goals
a primary interest
primary (adj.)
not derived from or reducible to something else; basic;
a primary instinct
primary (adj.)
of or being the essential or basic part;
Synonyms: elementary / elemental / basal