Green’s Dictionary of Slang

(Ling. Fr./Polari) the number eight; thus eightpence.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
1893		P.H. Emerson Signor Lippo 54: I’ll take otto soldi, that’s due soldi for baking and six soldi for navs.
2019		P. Baker Fabulosa 296/1: otter eight.
2023		R. Milward Man-Eating Typewriter 20: [O]ne of otta or nobba possible omis.