Or search: aba, hem, rep, wad, web, atom, cord, duck, floc, foam, info, jean, knit, lace, lame
2 Syllables: SU
cereal, cheerful, Cyril, fearful, filial, Israel, Israel's, lineal, medial, menial, serial, tearful, trivial, venial, virile, vitriol
3 Syllables: USU
arterial, bacterial, convivial, ethereal, funereal, imperial, materials, remedial, venereal
4 Syllables: UUSU
immaterial, magisterial, managerial, ministerial, uncongenial

Found 30 words across 3 groupings. Skipped 1 excess word of a similar stem.