Groundnut \Ground"nut`\ (ground"n[u^]t`), n. (Bot.) (a) The fruit of the {Arachis hypog[ae]a} (native country uncertain); the peanut; the earthnut. (b) A leguminous, twining plant ({Apios tuberosa}), producing clusters of dark purple flowers and having a root tuberous and pleasant to the taste. (c) The dwarf ginseng ({Aralia trifolia}). [U. S.] --Gray. (d) A European plant of the genus {Bunium} ({B. flexuosum}), having an edible root of a globular shape and sweet, aromatic taste; -- called also {earthnut}, {earth chestnut}, {hawknut}, and {pignut}. [1913 Webster]