1.  peanut(n = noun.plant) - underground pod of the peanut vine;
is a kind of pod, seedpod
is a part of arachis hypogaea, peanut, peanut vine

2.  peanut(n = noun.plant) arachis hypogaea, peanut vine - widely cultivated American plant cultivated in tropical and warm regions; showy yellow flowers on stalks that bend over to the soil so that seed pods ripen underground;
is a kind of legume, leguminous plant
has parts: earthnut, goober, goober pea, groundnut, monkey nut, peanut, peanut
is a member of arachis, genus arachis

3.  peanut(n = noun.person) - a young child who is small for his age;
is a kind of child, fry, kid, minor, nestling, nipper, shaver, small fry, tiddler, tike, tyke, youngster

4.  peanut(n = noun.food) earthnut, goober, goober pea, groundnut, monkey nut - pod of the peanut vine containing usually 2 nuts or seeds; `groundnut' and `monkey nut' are British terms;
is a kind of edible nut
is a part of arachis hypogaea, peanut, peanut vine

   peanut(s = adj.all) insignificant - of little importance or influence or power; of minor status; "a minor, insignificant bureaucrat"; "peanut politicians"

   The fruit of a trailing leguminous plant (Arachis hypogæa); also, the plant itself, which is widely cultivated for its fruit. [1913 Webster]
" The fruit is a hard pod, usually containing two or three seeds, sometimes but one, which ripen beneath the soil. Called also earthnut, groundnut, and goober." [1913 Webster]

peanut, n.
1 a leguminous plant, Arachis hypogaea, bearing pods that ripen underground and contain seeds used as food and yielding oil.
2 the seed of this plant.
3 (in pl.) colloq. a paltry or trivial thing or amount, esp. of money.

Idiom:
peanut butter a paste of ground roasted peanuts.

hog peanut, peanut bar, peanut brittle, peanut butter, peanut gallery, peanut oil, peanut vine, peanut worm, wild peanut