polysyllable

Polysyllable, pol′i-sil-a-bl, n. a word of many or of more than three syllables.
Chambers's Twentieth Century Dictionary (part 3 of 4: N-R)|Various
The formidable polysyllable simply means, "Hatchets rattling inside the baskets of the carpenters."
Samoa, A Hundred Years Ago And Long Before|George Turner
"Answer me, you—" He added a brisk polysyllable in Mixo-Lydian, with the desired effect.
The Ego Machine|Henry Kuttner
Yes, it is a polysyllable'—as, indeed, he had added an unnecessary syllable.
The Young Step-Mother|Charlotte M. Yonge

(crossing herself with superstitious awe at the polysyllable).
The Cloister and the Hearth|Charles Reade

British Dictionary definitions for polysyllable

polysyllable

/ (ˈpɒlɪˌsɪləbəl) /

noun

a word consisting of more than two syllables

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012