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.
"to attack in a mob, crowd round and annoy or beset," transitive, 1709, from mob (n.). Meaning "to form into a mob" is from 1711. Related: Mobbed; mobbing.
a type of woman's indoor cap with a bag-shaped crown and a broad band and frills, 1795 (as simply mob, 1748), from cap (n.) + obsolete mob (n.) "negligent attire" (1660s), earlier "a strumpet" (earlier form mab, 1550s), which is related to the obsolete verb mob "to tousle the hair, to dress untidily" (1660s), and perhaps is ultimately from mop (n.), but has been influenced by Mab as a female name. Dutch has a similar compound, mopmuts, but the relationship between it and the English word is uncertain.
early 15c. in astronomy, "outer sphere of the universe" (the primum mobile), from mobile (adj.); the artistic sense "abstract sculpture consisting of parts suspended so as to move," associated with Alexander Calder, is by 1939, perhaps a shortening of mobile sculpture (1936). Now-obsolete sense of "the common people, the rabble" (1670s, short for Latin mobile vulgus) led to mob (n.). Middle English had moble, moeble (mid-14c.) "movable goods, personal property," from Old French moble, meuble, from the Latin adjective, but in 16c. this was replaced by furniture.
"government by the rabble," 1580s, from French ochlocratie (1560s), from Greek okhlokratia (Polybius) "mob rule," the lowest grade of democracy, from kratos "rule, power, strength" (see -cracy) + okhlos "(orderless) crowd, multitude, throng; disturbance, annoyance," which is probably literally "moving mass," from PIE *wogh-lo-, suffixed form of root *wegh- "to go, move." "Several possibilities exist for the semantic development: e.g. an agent noun *'driving, carrying, moving', or an instrument noun *'driver, carrier, mover'. ... An original meaning 'drive' could easily develop into both 'stirred mass, mob' and 'spiritual excitement, unrest'" [Beekes]. For sense development, compare mob (n.). Related: Ochlocrat, ochlocratic; ochlocratical. Greek also had okhlagogos "mob-leader, ochlagogue."
It forms all or part of: commotion; emotion; mob; mobile; moment; momentary; momentous; momentum; motif; motility; motion; motive; moto-; motor; move; movement; mutiny; premotion; promote; remote; remove.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit kama-muta "moved by love" and probably mivati "pushes, moves;" Greek ameusasthai "to surpass," amyno "push away;" Latin movere "move, set in motion;" Lithuanian mauti "push on."