The Collaborative International Dictionary of English v.0.48:
Tankard \Tank"ard\, n. [OF. tanquart; cf. OD. tanckaert; of uncertain origin.] A large drinking vessel, especially one with a cover. [1913 Webster] Marius was the first who drank out of a silver tankard, after the manner of Bacchus. --Arbuthnot. [1913 Webster]WordNet (r) 3.0 (2006):
tankard n 1: large drinking vessel with one handle