What is a nautical mile?

• A. A unit of distance equal to 1 minute of latitude (about 1.1508 miles or 1.852 kilometers)
• B. A unit of time equal to 60 seconds
• C. A measure of weight used for cargo
• D. A distance equal to one degree of latitude

Answer: (B)

A nautical mile is a distance unit used in navigation. It is defined as the length of one minute of latitude along a meridian, which is 1/60 of a degree. That distance works out to about 1.852 kilometers or 1.1508 miles. In practice, speeds are given in knots, meaning nautical miles per hour, tying travel speed directly to this unit. One degree of latitude equals 60 nautical miles, so a degree is much larger than a single nautical mile. The other interpretations (a unit of time, a weight for cargo, or a distance equal to a full degree) don’t describe a nautical mile.