axis, center, center of action, center of gravity, centroid, centrum, core, dead center, epicenter, heart, hub, kernel, marrow, medulla, metacenter, middle, nave, nub, nucleus, omphalos, pith, pivot, storm center, umbilicus
middle, midst, mediety, mean, medium, middle term, center &c, mid-course, mezzo termine, juste milieu, halfway house, nave, navel
, omphalos, nucleus, nucleolus, equidistance, bisection, half distance, equator, diaphragm, midriff, intermediate, middle, medial, mesial, mean, mid, median, average, middlemost, midmost, mediate, intermediate, equidistant, central, mediterranean, equatorial, homocentric, in the middle, midway, halfway, midships, amidships, in medias res.
centrality, centricalness, center, middle, focus, core, kernel, nucleus, nucleolus, heart, pole axis, bull's eye, nave, navel
, umbilicus, backbone, marrow, pith, vertebra, vertebral column, hotbed, concentration, centralization, symmetry, center of gravity, center of pressure, center of percussion, center of oscillation, center of buoyancy, metacenter, central, centrical, middle, azygous, axial, focal, umbilical, concentric, middlemost, rachidian, spinal, vertebral, middle, midst, centrally.