Definition: A meter (symbol: m) is the base unit of length in the International System of Units (SI). It is defined as the distance light travels in a vacuum in 1/299,792,458 of a second. The meter is the foundation for other metric units of length, such as the kilometer and millimeter.

History/origin: The meter was originally defined in 1793 during the French Revolution as one ten-millionth of the distance from the Earth's equator to the North Pole along a meridian. Over time, this definition evolved through the use of physical artifacts and later through more precise scientific constants. The current definition based on the speed of light was adopted in 1983 to ensure consistency and accuracy.

Current use: The meter is universally used across the globe for measuring length and distance in both everyday and scientific contexts. It is the standard unit in most fields, including construction, engineering, physics, and transportation. As part of the metric system, it is favored for its simplicity and ease of conversion with other metric units.

Definition: A foot (plural: feet, symbol: ft) is a unit of length in the imperial and U.S. customary systems of measurement. One foot is equal to 12 inches and is exactly defined as 0.3048 meters. It is commonly used to measure height, distance, and dimensions in non-metric countries.

History/origin: The foot has ancient origins and was historically based on the length of a human foot. It was used in many different cultures, including the Romans, Greeks, and Chinese, with varying definitions. The current international foot was defined in 1959 through an agreement between English-speaking nations, standardizing it to exactly 0.3048 meters.

Current use: The foot is primarily used in the United States, as well as in the United Kingdom and Canada for certain applications. It is widely used in construction, aviation, and real estate to measure height, elevation, and floor plans. Despite the global shift to the metric system, the foot remains prevalent in everyday use in countries that have not fully adopted metric standards.