Definition of "secondary"

secondary

/ˈsɛkənd(ə)ɹɪ/

adjective
not generally comparable, comparative more secondary, superlative most secondary
1. Next in order to the first or primary; of second place in origin, rank, etc.
2. Originating from a deputy or delegated person or body.
3. (organic chemistry) Derived from a parent compound by replacement of two atoms of hydrogen by organic radicals.
4. (geology) Produced by alteration or deposition subsequent to the formation of the original rock mass.
5. (geology) Developed by pressure or other causes.
6. (anatomy) Pertaining to the second joint of the wing of a bird.
7. (medicine) Dependent or consequent upon another disease, or occurring in the second stage of a disease.
8. Of less than primary importance.
  Quotations
  the problem of sexual equality became even more secondary than before in the eyes of the kibbutz and of its women members.
  1992, Deborah Bernstein, Pioneers and Homemakers: Jewish Women in Pre-state Israel, page 227
9. (education) Related to secondary education, i.e. schooling between the ages of (approximately) 11 and 18.
10. (manufacturing) Relating to the manufacture of goods from raw materials.
11. (of a color) Formed by mixing primary colors.
12. (taxonomy, not comparable) Representing a reversion to an ancestral state.
  Quotations
  With the exception of a secondary loss in Dimecoenia, larvae of Ephydrini have prominent, ventral prolegs that bear crochets.
  2016 May 27, Wayne M. Matthis, Luciane Marinoni, “Revision of Ephydrini Zetterstedt (Diptera: Ephydridae) from the Americas south of the United States”, in Zootaxa, volume 4116, number 1
noun
plural secondaries
1. (ornithology) Any flight feather attached to the ulna (forearm) of a bird.
2. (aviation) A radar return generated by the response of an aircraft's transponder to an interrogation signal broadcast by a radar installation, containing additional encoded identification and situational data not available from a simple primary return.
3. (military) The second stage of a multistage thermonuclear weapon, which generates a fusion explosion when imploded as an indirect result of the fission explosion of the primary, and which, in a few extremely large weapons, itself implodes a fusion tertiary.
4. (finance) An act of issuing more stock by an already publicly traded corporation.
5. (American football, Canadian football) The defensive backs.
6. (electronics) An inductive coil or loop that is magnetically powered by a primary in a transformer or similar.
7. One who occupies a subordinate or auxiliary place; a delegate deputy.
  Quotations
  Old Escalus […] is thy secondary.
  c. 1603–1604 (date written), William Shakespeare, “Measure for Measure”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene i]
8. (astronomy) A secondary circle.
9. (astronomy) A satellite.
10. (education) A secondary school.
11. Short for secondary colour.
12. Anything secondary or of lesser importance.