trisyllable

UK: /traɪˈsɪləb^əl/ US: (trī′sil′ə bəl, trī sil′-, tri-)

WordReference Random House Unabridged Dictionary of American English © 2025

tri•syl•la•ble  (trī′sil′ə bəl, trī sil′-, tri-), n. 

1. Phonetics, Poetry a word of three syllables, as pendulum.

• 1580–90; tri- + syllable, modeled on Greek trisýllabos having three syllables

tri•syl•lab•ic  (trī′si lab′ik, tris′i-), tri′syl•lab′i•cal, adj.  tri′syl•lab′i•cal•ly, adv. 
tri•syl′lab•ism, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

trisyllable / traɪˈsɪləb^əl/ noun

1. a word of three syllables

trisyllabic / ˌtraɪsɪˈlæbɪk/, ˌtrisylˈlabical adjective