There are 8 13-letter words that end with 'iums'.
| epithalamiums | quinquenniums |
| radiothoriums | praseodymiums |
| protactiniums | superpremiums |
| unnilpentiums | unnilquadiums |
Note: These 8 13-letter words that end with 'iums' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words end with niums, riums, diums, liums, miums, biums, tiums, ciums, siums, viums, giums, hiums, piums, uiums, xiums, ziums.
6-letter words end with 'iums' (2)