[Bed-wins]. The homeless street poor are so called. Thus the Times calls the ragged, houseless boys “the Bedouins of London” The Bedouins are the nomadic tribes of Arabia (Arabic, bedawin, a dweller in a desert; badw, a desert). (See Street Arabs.)
“These Bedouins of the prairie invariably carry their lodges with them.” —A. D. Richardson: Beyond the Mississippi, chap. v.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894