What is "iambuses"

Iambus \I*am"bus\, n.; pl. L. Iambi, E. Iambuses. [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.] (Pros.) A foot consisting of a short syllable followed by a long one, as in [a^]m[=a]ns, or of an unaccented syllable followed by an accented one, as invent; an iambic. See the Couplet under Iambic, n.

n. (plural of iambus English)