"edible fungus," 1591, from M.Fr. trufle (1370), from O.Fr. truffe, probably from O.Prov. trufa, metathesized from L.L. tufera (pl.), cognate of L. tuber "edible root." Another theory notes It. tartuffo (Milanese tartuffel) "potato," supposedly from terræ tuber. Extended 1926 to powdered, round chocolates that look like truffles.