Green’s Dictionary of Slang

dive n.2

[SE dive. The implication is of both physical and social ‘lowness’; such places were usu. situated in a basement, cellar or other slightly clandestine place into which patrons could ‘dive’ without being noticed. Dive reached its heyday with US Prohibition (1920–33) but the term dive bar has persisted, lending an air of spurious romance to otherwise unexceptional drinking places]

1. [mid-19C+] (orig. US) an illicit drinking establishment or any similarly down-market place of entertainment, a brothel.

2. [1910s] (drugs) an opium den.

3. [late 19C+] any unappealing place; a slum, any form of run-down housing.

4. any place, irrespective of quality.