What does "hexameter" mean?

Hexameter: 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 Æneid 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.