iambus, n. [L. iambus, Gr. ; prob. akin to to throw, assail (the iambus being first used in satiric poetry), and to L. jacere to throw. Cf. Jet a shooting forth.].
A foot consisting of a short syllable followed by a long one, as in , or of an unaccented syllable followed by an accented one, as invent; an iambic. See the Couplet under Iambic, n. [1913 Webster]