11. (Naut.) (a) A division of the log line, serving to measure the rate
of the vessel's motion. Each knot on the line bears the same proportion
to a mile that thirty seconds do to an hour. The number of knots which
run off from the reel in half a minute, therefore, shows the number of
miles the vessel sails in an hour. Hence: (b) A nautical mile, or
6080.27 feet; as, when a ship goes eight miles an hour, her speed is
said to be eight knots.