Castor rhymes with:
caster, kaster, aster, astor, blaster, caster, disaster, faster, gaster, grandmaster, headmaster, jaster, kaster, laster, macmaster, master, mcmaster, oleaster, paster, pastor, pasztor, pilaster, plaster, raster
Castor sounds like:
cacciatore, cadre, caster, castoro, castro, cater, caterer, cather, catheter, cedar, ceder, cestaro, cetera, chatter, chaudhry, cheater, cheddar, chester, chichester, chitra, chitrao, chitter, chodorow, chowder, chowdhury, cider, citro, coaster, coauthor, coder, coderre, cooter, costar, costeira, coster, costra, coterie, cotter, cottier, couture, couturier, cowdery, cowdrey, cuadra, custer, cuter, cutrer, cutter, cytherea