Here's what rhymes with planetarium.
barium aquarium honorarium sanitarium vivarium Words that almost rhyme with planetarium
carrion nobelium agrarian ovarian barbarian proletarian libertarian trinitarian clarion sanitarian humanitarian librarian egalitarian sectarian antiquarian vegetarian chameleon seminarian nonagenarian vulgarian cnidarian authoritarian utilitarian totalitarian communitarian octogenarian parliamentarian nonsectarian centenarian veterinarian latitudinarian sexagenarian disciplinarian septuagenarian valetudinarian millennium gentium biennium fermium requiem lutetium compendium proscenium technetium quadrennium endometrium lawrencium