Open English Wordnet
Nouns
(n)marrow, marrow squash, vegetable marrowany of various squash plants grown for their elongated fruit with smooth dark green skin and whitish flesh
(n)kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-grittythe 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”