From Longman Dictionary of Contemporary Englishpentameterpen‧tam‧e‧ter /penˈtæmɪtə $ -ər/ noun [countable, uncountable] ALa line of poetry with five beats, or the beat of a poem like this → iambic pentameter
Examples from the Corpus
pentameter• It is written in basic pentameter with exactly ten stressed syllables in every single line.• Then he began a speech, and it could have been iambic pentameter. 