late 14c., copulacioun, "a coupling, joining, uniting," from Latin copulationem (nominative copulatio) "a coupling, joining, connecting," noun of action from past-participle stem of copulare "join together, couple, bind, link, unite," from copula "band, tie, link" (see copulate). Specific sense of "sexual intercourse, coition" is from late 15c., and this became the main sense from 16c.
1540s, "a going together, a coming together," from Late Latin coitionem (nominative coitio) "a coming together, a meeting; copulation," noun of action from coitus, past participle of coire "to go together, come together" (see coitus). Sexual meaning "copulation" is attested in English from 1610s (coiture in the same sense is from 1570s).
especially of animals, "desire copulation, be under the influence of sexual passion," late 14c., ruteien, from rutei, probably an Anglo-French form of the noun (see rut (n.2)). Related: Rutted; rutting.
mid-14c., "the joining of one thing to another," verbal noun from couple (v.). From late 14c. as "the joining of two persons in love or marriage," also "copulation." Meaning "that which couples or connects" is from 1540s.
"a thing done, a feat or action, good or bad," early 13c., verbal noun from do (v.). From early 14c. as "performance or execution of something." In the former sense, now usually in plural, doings. From c. 1600-1800 it also was a euphemism for "copulation."
"copulation, sexual intercourse," 1848, scientific use of Latin coitus "a meeting together; sexual union," past participle of coire "to come together, meet," from assimilated form of com "together" (see co-) + ire (past participle itus) "to come, to go," (from PIE root *ei- "to go").
In Middle English nativized as coite (early 15c.). Coitus was used in English in general senses of "meeting, uniting," and also in reference to magnetic force, planetary conjunction, etc., before the sexual sense came to predominate.
Coitus interruptus, "sexual intercourse in which the penis is voluntarily withdrawn from the vagina before ejaculation, for the purpose of avoiding conception," is from 1886 (from 1885 in German publications). Coitus reservatus in reference to prolonged copulation by deliberate control is from 1890 in English (1880 in German).
mid-15c., bottyne "plunder taken from an enemy in war," from Old French butin "booty" (14c.), from a Germanic source akin to Middle Low German bute "exchange." Influenced in form and sense (toward "profit, gain," whether taken by force or not) by boot (n.2) and in form by nouns ending in -y. Meaning "female body considered as a sex object" is 1920s, African-American vernacular. As with other male sexual terms for women, its sense can shift to copulation generally or to the eroticized body parts (compare nookie, ass, etc.).