1590s "fine or light," also "evaporating rapidly" (c. 1600), from French volatile, from Latin volatilis "fleeting, transitory; swift, rapid; flying, winged," from past participle stem of volare "to fly" (see volant). Sense of "readily changing, flighty, fickle" is first recorded 1640s. Volatiles in Middle English meant "birds, butterflies, and other winged creatures" (c. 1300).
late 14c., pliaunt, "capable of being easily bent, flexible, supple," from Old French ploiant "bending, supple; compliant, fickle," as a noun, "turncoat" (13c.), present participle of ploier "to bend," from Latin plicare "to fold, lay" (from PIE root *plek- "to plait"). Figurative sense of "readily influenced (for good or ill), easily persuaded" is from c. 1400. Related: Pliancy.
"simple machine consisting of a rigid piece acted upon at different points by two forces," c. 1300, from Old French levier (12c.) "a lifter, a lever, crowbar," agent noun from lever "to raise" (10c.), from Latin levare "to raise," from levis "light" in weight, "not heavy," also, of motion, "quick, rapid, nimble;" of food, "easy to digest;" figuratively "slight, trifling, unimportant; fickle, inconsistent;" of punishments, etc., "not severe," from PIE root *legwh- "not heavy, having little weight." As a verb, 1856, from the noun.
late 13c., wenche "girl, young woman," especially if unmarried, also "female infant," shortened from wenchel "child," also in Middle English "girl, maiden," from Old English wencel, probably related to wancol "unsteady, fickle, weak," from Proto-Germanic *wankila- (source also of Old Norse vakr "child, weak person," Old High German wanchal "fickle"), from PIE *weng- "to bend, curve" (see wink (v.)).
The wenche is nat dead, but slepith. [Wyclif, Matthew ix.24, c. 1380]
In Middle English occasionally with disparaging suggestion, and secondary sense of "concubine, strumpet" is attested by mid-14c. Also "serving-maid, bondwoman, young woman of a humble class" (late 14c.), a sense retained in the 19c. U.S. South in reference to slave women of any age. In Shakespeare's day a female flax-worker could be a flax-wench, flax-wife, or flax-woman.
1680s, "disorderly part of the population, rabble, common mass, the multitude, especially when rude or disorderly; a riotous assemblage," slang shortening of mobile, mobility "common people, populace, rabble" (1670s, probably with a conscious play on nobility), from Latin mobile vulgus "fickle common people" (the Latin phrase is attested c. 1600 in English), from mobile, neuter of mobilis "fickle, movable, mobile" (see mobile (adj.)).
Mob is a very strong word for a tumultuous or even riotous assembly, moved to or toward lawlessness by discontent or some similar exciting cause. Rabble is a contemptuous word for the very lowest classes, considered as confused or without sufficient strength or unity of feeling to make them especially dangerous. [Century Dictionary, 1897]
Also used of a promiscuous aggregation of people in any rank of life (1680s), and in Australia and New Zealand used without disparagement for "a crowd." Meaning "gang of criminals working together" is from 1839, originally of thieves or pick-pockets; the American English sense of "organized crime in general" is from 1927.
The Mob was not a synonym for the Mafia. It was an alliance of Jews, Italians, and a few Irishmen, some of them brilliant, who organized the supply, and often the production, of liquor during the thirteen years, ten months, and nineteen days of Prohibition. ... Their alliance — sometimes called the Combination but never the Mafia — was part of the urgent process of Americanizing crime. [Pete Hamill, "Why Sinatra Matters," 1998]
Mob scene "crowded place" is by 1922, from earlier use in reference to movies and theatrical productions; mob-rule "ochlocracy" is by 1806.
late 15c. (Caxton), "capable of movement, capable of being moved, not fixed or stationary," from Old French mobile (14c.), from Latin mobilis "movable, easy to move; loose, not firm," figuratively, "pliable, flexible, susceptible, nimble, quick; changeable, inconstant, fickle," contraction of *movibilis, from movere "to move" (from PIE root *meue- "to push away"). Sociology sense of "able to move into different social levels" is by 1927. Mobile home "large trailer permanently parked and used as a residence" is recorded by 1936. Mobile phone is by 1983.
A long-distance number tapped into an Illinois Bell car telephone glowed red on a display. Satisfied that the digits were correct, I pushed the SEND button on the phone. Familiar beeps and boops emerged from the handset. Then, before a half block of this Chicago suburb had slipped by, I was in contact with my New York office. ["Take-along Telephones," Popular Science, October 1983]