Definition of: triseme

(trī′sēm) noun
A syllable or foot consisting of or equivalent to three morae or short syllables, as the tribrach, iambus, and trochee.
—adjective Consisting of or equal to three morae or short syllables: also tri·se·mic (trī·sē′mik). [<Gk. trisēmos <tri- three + sēma a sign]