Green’s Dictionary of Slang

the HolbornCasino.

1854		Illus. London Mag. Dec. 227/2: ‘Let’s go to the Cas.?’ ‘Cas’ be d—d! [...] Beastly place, where you fellows go every night to lounge about and see snobs dancing!’.
1857		Paul Pry (London) 15 Aug. n.p.: Fred thought there was no spot in London equal to the Manor House. He would concede the prestige to Cremorne and the Cas.