hex·am·e·ter 
(hĕk-sămĭ-tər)
(hĕk-sămĭ-tər)n.
1. Verse written in lines of six metrical feet, especially classical verse in which the first four feet of each line are either dactylic or spondaic, the fifth dactylic, and the sixth spondaic.
2. A single line of such verse.
[Latin, from Greek hexametros, having six metrical feet : hexa-, hexa- + metron, meter; see METER1.]
hex′a·metric (hĕk-sə-mĕtrĭk), hex′a·metri·cal (-rĭ-kəl) adj.