Source : Webster's Revised Unabridged Dictionary (1913)

Hexameter \Hex*am"e*ter\, n. [L., fr. Gr. ? of six meters; (sc.
   ?) hexameter verse; "e`x six + ? measure: cf. F.
   hexam[`e]tre. See {Six}, and {Meter}.] (Gr. & Lat. Pros.)
   A verse of six feet, the first four of which may be either
   dactyls or spondees, the fifth must regularly be a dactyl,
   and the sixth always a spondee. In this species of verse are
   composed the Iliad of Homer and the [AE]neid of Virgil. In
   English hexameters accent takes the place of quantity.

         Leaped like the | roe when he | hears in the | woodland
         the | voice of the | huntsman.           --Longfellow.

         Strongly it | bears us a- | long on | swelling and |
         limitless | billows, Nothing be- | fore and | nothing
         be- | hind but the | sky and the | ocean. --Coleridge.

Hexameter \Hex*am"e*ter\, a.
   Having six metrical feet, especially dactyls and spondees.
   --Holland.

Source : WordNet®

hexameter
     n : a verse line having six metrical feet