ἑφθημιμερής

A. containing seven halves, i.e. 3 1/2: esp. in metre, -μερές,τό, a measure of three feet and a half, such as the first 3 1/2 feet of a Hexameter or Iambic Trimeter, Heph. 7.3, Sch.Ar. Pl. 302 (pl.), etc.; ἑ. τομή a caesura after such a phrase, Aristid. Quint. 1.25.