a metrical foot consisting, in Greek and Latin verse, of one short syllable followed by one long one, or, as in English verse, of one unaccented syllable followed by one accented one (Ex.: “Tŏ stríve, tŏ séek, tŏ fínd, ănd nót tŏ yíeld”)
Fr iambe < L iambus < Gr iambos
See iamb in American Heritage Dictionary 4
nounpl.i·ambs also i·am·bus·es or i·am·bi(-bīˌ)
A metrical foot consisting of an unstressed syllable followed by a stressed syllable or a short syllable followed by a long syllable, as in delay.