Polygram rhymes with:
anagram, cablegram, centigram, diagram, electrocardiogram, engram, epigram, histogram, hologram, kilogram, logogram, mailgram, mammogram, microgram, milgram, milligram, monogram, pegram, program, programme, reprogram, sonogram, telegram, wolfgram
Polygram sounds like:
pelagreeny, pellegrin, pellegrini, pellegrino, pilgram, pilgreen, pilgrim, pleasurama, polychrome