earthnut
noun
1.
any of various highly prized edible subterranean fungi of the genus Tuber; grow naturally in southwestern Europe
2.
a common European plant having edible tubers with the flavor of roasted chestnuts
3.
pod of the peanut vine containing usually 2 nuts or seeds; ‘groundnut’ and ‘monkey nut’ are British terms
4.
edible subterranean fungus of the genus Tuber