Definitions of earthnut:

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