[1] : The Collaborative International Dictionary of English v.0.48

groundnut \ground"nut`\ ground"nu^t`, n. bot.
   a the fruit of the arachis hypogaea 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
see also:
arachis hypogaea apios tuberosa aralia trifolia bunium b. flexuosum earthnut 
earth chestnut hawknut pignut 

[2] : The Collaborative International Dictionary of English v.0.48

pignut \pig"nut\ pi^g"nu^t, n. bot.
   a see groundnut
   d .
   b the bitter-flavored nut of a species of hickory carya
       glabra syn. carya porcina; also, the tree itself.
       1913 webster
see also:
groundnut carya glabra carya porcina 

[3] : WordNet (r) 2.0

pignut
     n : an american hickory tree having bitter nuts syn: pignut
         hickory, brown hickory, black hickory, carya glabra
see also:
pignut hickory brown hickory black hickory carya glabra 

Pignut >> P Words
Pignut, definition of term: Pignut
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