THESAURUS
sigmoid
Cynthian, S-shaped, ambagious, anfractuous, bicorn, circuitous, circumlocutory, convolutional, corniform, crescent, crescent-shaped, crescentic, crescentiform, crescentlike, falcate, falciform, flexuose, flexuous, horn-shaped, horned, involute, involuted, involutional, labyrinthine, lunar, lunate, luniform, lunular, mazy, meandering, meandrous, menisciform, meniscoid, moon-shaped, moonlike, rivose, rivulose, roundabout, ruffled, semicircular, semilunar, serpentine, sickle-like, sickle-shaped, sinuate, sinuose, sinuous, snaky, torsional, tortile, tortuous, turning, twisting, twisty, two-horned, whorled, winding, wreathlike, wreathy
ROGET THESAURUS
sigmoid
Convolution
N
convolution, winding, convolution, involution, circumvolution, wave, undulation, tortuosity, anfractuosity, sinuosity, sinuation, meandering, circuit, circumbendibus, twist, twirl, windings and turnings, ambages, torsion, inosculation, reticulation, rivulation, roughness, coil, roll, curl, buckle, spiral, helix, corkscrew, worm, volute, rundle, tendril, scollop, scallop, escalop, kink, ammonite, snakestone, serpent, eel, maze, labyrinth, knot, convoluted, winding, twisted, tortile, tortive, wavy, undated, undulatory, circling, snaky, snake-like, serpentine, serpent, anguill, vermiform, vermicular, mazy, tortuous, sinuous, flexuous, anfractuous, reclivate, rivulose, scolecoid,
sigmoid, sigmoidal, spiriferous, spiroid, involved, intricate, complicated, perplexed, labyrinth, labyrinthic, labyrinthian, labyrinthine, peristaltic, daedalian, kinky, knotted, wreathy, frizzly, crepe, buckled, raveled, spiral, coiled, helical, cochleate, cochleous, screw-shaped, turbinated, turbiniform, in and out, round and round, a can of worms, Gordian knot.