I've just found out that a penny can be called a win in slang. It appears to be only used in British slang, and perhaps in Irish too.
Green’s Dictionary of Slang mentions below and gives the earliest citation from 1535:
win n.
also winn, wyn
[origin unknown, but Vaux suggests, without further explanation, an abbr. of Winchester; Ribton-Turner, A History of Vagrants (1887), suggests synon. Erse pinghin, Manx ping]1. a penny.
c.1535 [UK] R. Copland Hye way to the Spyttel House Eiii: For the bene bonse my watch hath a wyn.
However, GDoS also offers a second meaning in US English as 'cent':
2. (US) a cent (cf. penny n. (1)).
1859 [US] Matsell Vocabulum 96: win A cent.
If 'win' is an abbreviation of Winchester, how so? If not, why might it be referred to as 'win'? Could it be related to winning money, winnings?
Note: OED also states the same for the origin: "Origin obscure; quot. 1819 suggests that it may be short for Winchester." OED does not state that the word is obsolete.