Anlage, Kern, NMR, alpha particle, antibaryon, antilepton, antimeson, atomic nucleus, atomic particle, axiom, axis, baryon, basichromatin, beta particle, bud, center, center of action, center of gravity, centroid, centrum, chromatin, chromatin strands, core, dead center, diameter, diaphragm, egg, electron, elementary particle, elixir, embryo, epicenter, equator, essence, essential, flower, focus, fundamental, germ, germen, gist, gravamen, heart, heterochromatin, hub, hypostasis, inner essence, interior, karyosome, karyotin, kernel, lepton, loins, macronucleus, marrow, mean, meat, median, medulla, meganucleus, meson, metacenter, micronucleus, middle, midmost, midriff, midst, nave, navel, neutron, nub, nuclear force, nuclear magnetic resonance, nuclear particle, nuclear resonance, nucleolus, nucleon, nucleosynthesis, nuts and bolts, omphalos, ovum, photon, pith, pivot, plasmosome, postulate, principle, proton, quid, quiddity, quintessence, rudiment, sap, seed, soul, spark, spermatozoon, spirit, storm center, strangeness, strong interaction, stuff, substance, the nitty-gritty, thick, thick of things, triton, umbilicus, valence electron, waist, waistline, zone