groundnut

noun4

1. •
   A climbing vine, Apios americana, of eastern North America, having fragrant brownish flowers and small edible tubers.
2. •
   Any similar plant having underground tubers.
3. •
   A plant which bears its nutlike seeds underground, such as a peanut (Arachis hypogaea) or a Bambara groundnut (Vigna subterranea).
4. •
   The nutlike tuber of such a plant, especially peanuts.