The measurement of something from end to end or along its longest side, or a measurement of a particular part of something
Length conversion rates
1 Yard = 0.9144 Meters, as per the International yard and pound agreement of 1959.
1 Nautical mile = 1852 Meters, as per the First International Extraordinary Hydrographic Conference of 1929.
1 Foot = 0.3048 Meters
1 Inch = 0.0254 Meters
Measuring the extent of things by length is integral to quantifying size, and therefore value. Defunct units such as the cubit were easy to use however unreliable due to their reliance on people being the same size. As such, it measured the distance from a person’s elbow to fingertip. Still today, such human-based measurements are in use, their measurements now standardised. Notably feet (0.3048 meters), and also hands (0.1016 meters) for horses.
The current SI unit of length is the meter. It is measured as the distance that light can travel in a vacuum in exactly 1/299792458 seconds. During the French revolution, French scientists defined the original meter. So they stated that it was 1/10,000,000 of the distance between the North Pole and the equator, through Paris.
The imperial system, and the inch especially, traces back to England over 1,000 years ago. The width of a man’s thumb, similarly three barleycorns*, were the basic measure. In 1959 the international yard and pound was agreed upon. Henceforth this set the measurements at 0.9144 meters for the yard, and 0.45359237 kilograms for the pound. These are still in use to this day, and which determine all other metric-imperial conversions.
*three similarly well-grown grains of barley placed end to end