subs. (old).A sixpence. For synonyms, see BENDER.
1781. G. PARKER, A View of Society, II., 56. You give a shilling to buy a comb, for which he gives sixpence, so works you for another FYE-BUCK.
1885. Household Words, 20 June, p. 155. Buck is most likely a corruption of FYE-BUCK, a slang name for sixpence, which is now almost, if not altogether, obsolete.