`groundnut' and `monkey nut' are British terms

• Pod of the peanut vine containing usually 2 nuts or seeds
• Truffle, e.g.
• Grow naturally in southwestern Europe
• Edible subterranean fungus of the genus Tuber
• Plant with edible tuber
• A common European plant having edible tubers with the flavor of roasted chestnuts

Wikipedia Word definitions in Wikipedia
Earthnut is a common name for several unrelated plants which produce a subterranean edible seed, fruit or root Earthnut may refer to: Truffle Peanut Roots and tubers: Lathyrus tuberosus Conopodium majus Bunium persicum

WordNet Word definitions in WordNet
n. any of various highly prized edible subterranean fungi of the genus Tuber; grow naturally in southwestern Europe [syn: truffle , earth-ball ] a common European plant having edible tubers with the flavor of roasted chestnuts [syn: Conopodium denudatum ...

Wiktionary Word definitions in Wiktionary
n. 1 Any of various roots, tubers, or pods that grow underground. 2 # A tuber belonging to the species (taxlink Bunium flexuosum species noshow=1), (taxlink Carum bulbocastanum species noshow=1), (taxlink Conopodium denudatum species noshow=1), or (taxlink ...