Also called: earthnut any of various edible saprotrophic ascomycetous subterranean fungi of the European genus Tuber. They have a tuberous appearance and are regarded as a delicacy
2.
chiefly (Brit) Also called: rum truffle a sweet resembling this fungus in shape, flavoured with chocolate or rum
[C16: from French truffe, from Old Provençal trufa, ultimately from Latin tūber]
"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