Words That Rhyme With "Decennium" :
3 syllables:
conium, cranium, minium, rhenium
4 syllables:
actinium, ammonium, Asplenium, biennium, bucranium, calcaneum, compendium, delphinium, dickensian, didinium, dominium, einsteinium, euphonium, geranium, germanium, harmonium, helenium, hydronium, hymenium, Iconium, illinium, ionium, lawrencium, meconium, millennium, neptunium, phosphonium, plutonium, polonium, prytaneum, quadrennium, quinquennium, Rubensian, ruthenium, selenium, septennium, stramonium, sulfonium, sulphonium, syconium, titanium, triclinium, triennium, uranium, virginium, Waldensian, zirconium
5 syllables:
Albigensian, androconium, antependium, antimensium, archegonium, ascogonium, bimillennium, carpogonium, chondrocranium, condominium, cuprammonium, diazonium, endocranium, Herculaneum, oogonium, pandemonium, pelargonium, pericranium, perigonium, peritoneum, positronium, protactinium, salientian, sporogonium, succedaneum, suppedaneum, uredinium
6 syllables:
ferrotitanium, ferrozirconium, hexamethonium, protoactinium, spermatogonium