core

1 the seat of one's deepest thoughts and emotions in my very core I knew that an injustice was being committed Synonyms belly, blood, bone(s), bosom, breast, gut, heart, heartstrings, inner space, inside, quick, soul Related Words conscience, mind

2 a thing or place that is of greatest importance to an activity or interest the capitol building is the core of the political life of the state Synonyms axis, base, capital, central, center, cynosure, epicenter, eye, focus, ground zero, heart, hub, locus, mecca, navel, nerve center, nexus, nucleus, omphalos, seatRelated Words headquarters; happy hunting ground, hive, hotbed, hot spot, playground, playland; kernel, nub, pith; deep, thick; essence, quintessence, soul; attraction, lodestone (also loadstone), magnet, polestar

3 the central part or aspect of something under consideration at last, we come to the core of the issue that has been dividing us Synonyms bottom line, bull's-eye, centerpiece, crux, essence, gist, heart, kernel, keynote, meat, meat and potatoes, net, nub, nubbin, nucleus, pith, pivot, point, root, sumRelated Words course, direction, drift, tenor; body, content, substance; hypothesis, proposition, purport, subject, theme, thesis

4 the main or greater part of something as distinguished from its subordinate parts a starfish can even survive the division of its core into two parts; both halves then regenerate Synonyms brunt, bulk, chief, body, generality, heft [archaic], main, mass, staple, weightRelated Words majority; aggregate, amount, entirety, quantum, sum, sum total, total, totality, whole; bottom, essence, essentiality, marrow, meat, nature, pith, quintessence, root, soul, stuff, substance; center, heart, hub, kernel, middle, nucleus, nut, seat; affair, argument, burden, crux, focus, gist, nub, pitch, point, purport; matter, motif, subject, text, theme, topicNear Antonyms accessory (also accessary), adjunct, appendage, extension, offshoot; component, constituent, element, ingredient; division, part, piece, section, segment; angle, aspect, facet, feature, quality, side

5 an area or point that is an equal distance from all points along an edge or outer surface the mountain rises from ground that is almost precisely at the island's core Synonyms center, middle, midpoint, midstRelated Words inside, interiorAntonyms perimeter, periphery