(figuratively, slang) A narrow place of confinement, a cage; a jail, a prison.
Example: 'Tis the cruel gripe, / That lean hard-handed poverty inflicts, / The hope of better things, the chance to win, / The wiſh to ſhine, the thirſt to be amus'd, / That at the found of Winter's hoary wing, / Unpeople all our counties, of ſuch herds, / Of flutt'ring, loit'ring, cringing, begging, looſe, / And wanton vagrants, as make London, vaſt / And boundless as it is, a crowded coop.