THESAURUS
diameter
air line, amplitude, area, axis, beeline, bigness, bisector, body, bore, boundary, breadth, bulk, caliber, center, chord, core, coverage, depth, diagonal, diaphragm, dimension, dimensions, direct line, directrix, divider, edge, equator, expanse, expansion, extension, extent, gauge, girth, great-circle course, greatness, halfway mark, heart, height, interior, kernel, largeness, length, line of demarcation, magnitude, mass, mean, measure, measurement, median, middle, midmost, midriff, midst, normal, nucleus, partition, perpendicular, proportion, proportions, radius, radius vector, range, reach, right line, scale, scope, secant, segment, semidiameter, shortcut, side, size, spread, straight, straight course, straight line, straight stretch, straightaway, streamline, tangent, thick, thick of things, transversal, vector, volume, waist, waistline, width, zone
ROGET THESAURUS
diameter
Thickness,
N
breadth, thickness, breadth, width, latitude, amplitude,
diameter, bore, caliber, radius, superficial extent, thickness, crassitude, corpulence, dilation, broad, wide, ample, extended, discous, fanlike, outspread, outstretched, wide as a church-door, latifoliate, latifolous, thick, dumpy, squab, squat, thickset, thick as a rope.