subs. phr. (Irish).The ace of diamonds.[See quots.]
1830. W. CARLETON, Traits and Stories of the Irish Peasantry. What do you mean by the Earl of Cork? asked Mr. Squander. The ace of diamonds, your honour. Its the worst ace, and the poorest card in the pack, and is called the EARL OF CORK, because hes the poorest nobleman in Ireland.
1864. Athenæum, 29 Oct. The ace of diamonds acquired the name of the EARL OF CORK because his lordship happened to be the poorest nobleman in Ireland.