iambus \iam"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=ans, or of an unaccented syllable followed by
   an accented one, as invent; an iambic. see the couplet under
   iambic, n.
   1913 webster
see also:
iambi iambuses jet iambic