Meters
Definition: The meter (symbol: m) is the base unit of length in the International System of Units (SI), defined as the distance light travels in vacuum in 1/299,792,458 of a second.
History/Origin: Originally established in 1793 in France as one ten-millionth of the distance from the equator to the North Pole along a meridian through Paris. Redefined several times to increase precision, with the current definition based on the speed of light since 1983.
Current Use: Used globally as the fundamental standard of length for scientific, industrial, and everyday measurements.
Yards
Definition: The yard (symbol: yd) is an Imperial and U.S. customary unit of length equal to 0.9144 meters.
History/Origin: Derived from Old English and early medieval standards, the yard was officially defined in 1959 as exactly 0.9144 meters under the international yard agreement.
Current Use: Used mainly in the United States and the United Kingdom for measuring medium-length distances such as fabric, sports fields, and construction materials.