Plenum rhymes with:
denham, denim, denomme, menem, obshchestvennom, phenom, venom, aluminium, aluminum, annum, arcanum, barnum, bonum, branam, brannam, brannum, branum, bucknam, burnam, burnham, bynum, canam, debnam, denham, denim, denomme, dornam, downum, dunham, dunnam, duodenum, farnam, farnham, farnum, granum, greenham, hannam, hannum, interregnum, jeyaretnam, keenum, lanham, lannom, lanthanum, lanum, laudanum, linam, lynam, magnum, menem, mezhdumarodnom, molybdenum, newnam, obshchestvennom, organum, panem, phenom, platinum, putnam, puttnam, ranum, sonum, steinem, stoneham, swetnam, tottenham, tranum, tympanum, unum, vanname, vanornum, varnum, venom
Plenum sounds like:
pablum, palen, palimony, palin, pallone, palm, palma, palme, paloma, palomino, palomo, palone, paolini, paolino, papillion, papilloma, paulin, paulina, pauline, paulino, paullin, pavilion, pavillion, pelham, pelino, pellman, pellum, pelon, pflaum, pflum, phalen, phelan, philana, philemon, philene, philina, philomena, philon, phylum, pillion, pilon, pipeline, plain, plaino, plam, plamann, plan, plane, plano, playin', plein, pliny, plohn, plowman, plum, plume, poblano, poehlman, poelman, pohlman, pohlmann, polan, polen, polimeni, polin, polino, pollan, pollen, pollina, pollini, pollinia, pollino, pollman, pollyanna, polonium, poplin, poulin, pullam, pullan, pullano, pullen, pulliam, pullin, pullman, pullum, pylon