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22 words ending with um, 12 letters long

appressorium archesporium cladophyllum diverticulum epithalamium hibernaculum infundibulum nonpetroleum perionychium praseodymium protactinium prothalamium pseudopodium quinquennium radiothorium spermagonium superpremium superstratum transuranium unnilpentium unnilquadium xiphisternum