that which arouses or excites, 1968, originally of psychedelic drugs, from verbal phrase turn on "activate (a mechanism)" (1833), specifically from figurative sense turn (someone) on "excite, stimulate, arouse," recorded from 1903; from turn (v.) + on (adv.).

1590s, "to put on," from get (v.) + on (adv.). Meaning "prosper" is from 1785; that of "to advance, make progress" is from 1798; that of "be friendly" (with) is attested by 1816.

by 1969, originally in reference to the use of computers in education; see hand (n.) + on (adv.).

"intermittently, occasionally," 1530s; see off (adv.) + on. As an adjective, "occasional," from 1580s.

1580s, "advance, proceed," from go (v.) + on (adv.). Meaning "behave, carry on" is from 1777; especially "to talk volubly" (1863). As an expression of derision by 1886.

1909, "with one side facing," from side (n.) + on (adv.), perhaps based on earlier head-on. In reference to a vehicle collision, by 1828.

1590s, "act of putting on vestments" (a sense now found in investiture); later "act of being invested with an office, right, endowment, etc." (1640s); and "surrounding and besieging" of a military target (1811); from invest + -ment.

Commercial sense of "an investing of money or capital" is from 1610s, originally in reference to the East India Company; general use is from 1740 in the sense of "conversion of money to property in hopes of profit," and by 1837 in the sense "amount of money invested." For evolution of the commercial senses, see invest.

Old English gieldan (West Saxon), geldan (Anglian) "to pay, pay for; reward, render; worship, serve, sacrifice to" (class III strong verb; past tense geald, past participle golden), from Proto-Germanic *geldan "pay" (source also of Old Saxon geldan "to be worth," Old Norse gjaldo "to repay, return," Middle Dutch ghelden, Dutch gelden "to cost, be worth, concern," Old High German geltan, German gelten "to be worth," Gothic fra-gildan "to repay, requite"). This is from PIE *gheldh- "to pay," a root found only in Balto-Slavic and Germanic (and Old Church Slavonic žledo, Lithuanian geliuoti might be Germanic loan-words).

"[T]he only generally surviving senses on the Continent are 'to be worth; to be valid, to concern, apply to,' which are not represented at all in the English word" [OED]; sense development in English comes via use of this word to translate Latin reddere, French rendre. Sense of "give in return for labor or capital invested" is from early 14c. Intransitive sense of "give oneself up, submit, surrender (to a foe)" is from c. 1300. Related to Middle Low German and Middle Dutch gelt, Dutch geld, German Geld "money." Related: Yielded; yielding.

mid-14c., "invested with glory," past-participle adjective from glorify. Weakened sense of "transformed into something better" is from 1821.

1727, "adorned, ornamented, embellished," past-participle adjective from decorate (v.). From 1816 as "invested with a badge or medal of honor."