word-forming element meaning "many, much, multi-, one or more," from Greek polys "much" (plural polloi), from PIE root *pele- (1) "to fill," with derivatives referring to multitudinousness or abundance. Equivalent to Latin multi-, it is properly used in compounds only with words of Greek origin. In chemical names, usually indicating a compound with a large number of atoms or molecules of the same kind (such as polymer).
late 14c., from Anglo-French sillable, alteration of Old French silabe "syllable" (12c., Modern French syllabe), from Latin syllaba, from Greek syllabē "that which is held together; a syllable, several sounds or letters taken together," i.e. "a taking together" of letters; from syllambanein "take or put together, collect, gather," from assimilated form of syn- "together" (see syn-) + stem of lambanein "to take" (see lemma). The unetymological -le apparently is by analogy with participle and principle.
<a href="https://www.etymonline.com/word/polysyllable">Etymology of polysyllable by etymonline</a>
Harper, D. (n.d.). Etymology of polysyllable. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/polysyllable