Mob, n.
Etymology: [L. mobile vulgus, the movable common people. See Mobile, n.]
1. The lower classes of a community; the populace, or the lowest part of it. A cluster of mob were making themselves merry with their betters. Addison.
2. Hence: A throgn; a rabble; esp., an unlawful or riotous assembly; a disorderly crowd. The mob of gentlemen who wrote with ease. Pope. Had every Athenian citizen been a Socrates, every Athenian assembly would still have been a mob. Madison. Confused by brainless mobs. Tennyson. Mob law, law administered by the mob; lynch law. -- Swell mob, well dressed thieves and swindlers, regarded collectively. [Slang] Dickens.
3 other Webster entries under this spelling
Mob, n.
A mobcap. Goldsmith.
Mob, v. t.
To wrap up in, or cover with, a cowl. [R.]
Mob, v. t. [imp. & p. p. Mobbed; p. pr. & vb. n. Mobbing.]
To crowd about, as a mob, and attack or annoy; as, to mob a house or a person.
Shades of meaning
The populace are poor and ignorant, but may be law-abiding; a mob is disorderly and lawless, but may be rich and influential. The rabble is despicable, worthless, purposeless; a mob may have effective desperate purpose. A crowd may be drawn by mere curiosity; some strong, pervading excitement is needed to make it a mob. Compare people.