ROGET THESAURUS
omphalos
Middle
N
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.