Slum

google

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early 19th century (originally slang, in the sense ‘room’): of unknown origin.

wiktionary

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Early 19th century. Originally slang, in the sense "room", especially " backroom" [attested 1812]; of unknown origin.

See slumgullion.

etymonline

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slum (n.)

1845, from back slum "dirty back alley of a city, street of poor or low people" (1825), originally a slang or cant word meaning "room," especially "back room" (1812), of unknown origin. Related: slums. Slumscape is from 1947.

slum (v.)

"visit slums of a city," especially for diversion or amusement, often under guise of philanthropy, 1884, from slum (n.). A pastime popularized by East End novels. Earlier it meant "to visit slums for disreputable purposes or in search of vice" (1860). Related: Slumming.