groundnut

noun

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. The nutlike tuber of such a plant, especially peanuts.
4. A plant which bears its nutlike seeds underground, such as a peanut (Arachis hypogaea) or a Bambara groundnut (Vigna subterranea).