kernel

nouns

the inner and usually edible part of a seed or grain or nut or fruit stone
"black walnut kernels are difficult to get out of the shell"
kernel, meat
a single whole grain of a cereal
"a kernel of corn"
kernel
is a type of (narrower)
dry seed-like fruit produced by the cereal grasses: e.g. wheat, barley, Indian corn
caryopsis, grain
the choicest or most essential or most vital part of some idea or experience
"the gist of the prosecutor's argument"; "the heart and soul of the Republican Party"; "the nub of the story"
center, centre, core, essence, gist, heart, heart and soul, inwardness, kernel, marrow, meat, nitty-gritty, nub, pith, substance, sum