Here's what rhymes with colossum.
blossom possum opossum Words that almost rhyme with colossum
rosin caution cation soften libation precaution microcosm macrocosm tryptophan herniation calumniation bottom column solemn forum balsam dorsum bonum rostrum flotsam foursome slalom carom problem boredom mortem quorum condom sorghum drachm nostrum wampum thraldom thralldom cockscomb gastronome quantum decorum metronome stardom falciparum sugarplum postpartum