bullnoun,currencyfive shillings, a crown piece19-20; historical. Compare yoopetymology: pre-decimalisation (1971) a coin worth five shillings; perhaps from classical Latin bulla ‘anything of a round, circular nature’; attested by Galloway Tinkler-Gypsiesnote:
Grose and Egan (1823), Borrow (1874) attest bull as ‘a crown piece’