Word Study
antepenult
CIDE DICTIONARY
antepenult, n. [L. antepaenultima (sc. syllaba) antepenultimate; ante before + paenultimus the last but one; paene almost + ultimus last.].
The last syllable of a word except two, as -syl- in monosyllable. [1913 Webster]
OXFORD DICTIONARY
antepenult, n. the last syllable but two in a word.
Etymology
abbr. of LL antepaenultimus (as ANTE-, paenultimus PENULT)
For further exploring for "antepenult" in Webster Dictionary Online