a unit of length used to measure nautical distances or depths, in the U.S. equal to 120 fathoms or 720 ft (219.456 m): in Britain equal to 101.26 fathoms or 607.56 ft (185.184 m) or about one tenth of a nautical mile
See cable length in American Heritage Dictionary 4
also ca·ble's length(kāˈbəlz)
noun Nautical
A unit of length equal to 720 feet (220 meters) in the United States and 608 feet (185 meters) in England.