See core in Webster's New World Roget's A-Z Thesaurus II
noun
A point of origin from which ideas or influences, for example, originate:
bottom, center, focus, heart, hub, quick, root1. See startThe most central and material part:
essence, gist, heart, kernel, marrow, meat, nub, pith, quintessence, root1, soul, spirit, stuff, substance. (Law) gravamen. See be
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