1. First or highest in rank, quality, or importance; principal.
2. Being or standing first in a list, series, or sequence.
3. Occurring first in time or sequence; earliest.
4. Being or existing as the first or earliest of a kind; primitive.
5. Geology. Characteristic of or existing in a rock at the time of its formation.
6. Serving as or being an essential component, as of a system; basic. See synonyms at chief.
7. 1. Immediate; direct: a primary effect; a primary information source.
   2. Preliminary to a later stage in a continuing process: primary training.
   3. Of or relating to a primary school: the primary grades.
8. Of or relating to a primary color or colors.
9. Linguistics.
   1. Having a word root or other linguistic element as a basis that cannot be further analyzed or broken down. Used of the derivation of a word or word element.
   2. Referring to present or future time. Used as a collective designation for various present and future verb tenses in Latin, Greek, and Sanskrit.
10. Electronics. Of, relating to, or constituting an inducting current, circuit, or coil.
11. Of, relating to, or designating the main flight feathers projecting along the outer edge of a bird's wing.
12. Of or relating to agriculture, forestry, the industries that extract natural materials from the earth, or the products so obtained: a primary commodity.
13. Chemistry.
    1. Relating to the replacement of one of several atoms or radicals in a compound by another atom or radical.
    2. Having a carbon atom attached solely to one other carbon atom in a molecule.
14. Botany. Of, relating to, or derived from a primary meristem.

1. 1. One that is first in time, order, or sequence.
   2. One that is first or best in degree, quality, or importance.
   3. One that is fundamental, basic, or elemental.
2. 1. A meeting of the registered voters of a political party for the purpose of nominating candidates and for choosing delegates to their party convention.
   2. A preliminary election in which the registered voters of a political party nominate candidates for office.
3. A primary color.
4. A primary flight feather.
5. Electronics. An inducting current, circuit, or coil.
6. Astronomy.
   1. A celestial body, especially a star, relative to other bodies in orbit around it.
   2. The brighter of two stars that make up a double star.

[Middle English, from Latin prīmārius, chief, from prīmus, first.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.