What is an international nautical mile?
An international nautical mile is exactly 1,852 meters, which is about 1.15078 statute miles. The word 'nautical' distinguishes it from the statute mile used on land.
Because the nautical mile began as one minute of latitude, the Earth's circumference works out at roughly 21,600 nautical miles (360 degrees of 60 minutes each). Navigators measure distance directly off the latitude scale on a chart.
A tenth of a nautical mile is a cable, which is 185.2 meters and is still used for short distances at sea. Minutes and seconds belong to the angles of latitude and longitude, not to the unit itself.
What is a millimeter?
A millimeter is a thousandth of a meter (1/1000) which is the SI (International System of Units) unit of length. It is normally used to measure small lengths like the thickness of a sheet of paper or the dimensions of a small object.
One millimeter is approximately equal to 0.03937 inches (about 1/25th). Presicely there are 25.4 millimeters in an inch and it is often used in science and engineering. It is used in countries that have adopted the metric system.
You may come across millimeters when measuring the size of electronic components, jewelry or even the thickness of a fingernail.