Choriambus :: Choriambus (n.) A foot consisting of four syllables, of which the first and last are long, and the other short (- ~ ~ -); that is, a choreus, or trochee, and an iambus united..
Diiambus :: Diiambus (n.) A double iambus; a foot consisting of two iambuses (/ / / /).
Iambus :: Iambus (n.) A foot consisting of a short syllable followed by a long one, as in /mans, or of an unaccented syllable followed by an accented one, as invent; an iambic. See the Couplet under Iambic, n..