Definition: A centimeter (symbol: cm) is a unit of length in the metric system, equal to one-hundredth of a meter (0.01 m). It is commonly used for measuring moderate lengths and distances in everyday life, science, and engineering.

History/origin: The centimeter is derived from the meter, which was first defined in 1793 during the French Revolution as one ten-millionth of the distance from the equator to the North Pole along a meridian. The metric system was designed to be a universal and standardized system of measurement, and the centimeter emerged as a convenient unit for medium-scale measurements.

Current use: The centimeter is widely used worldwide in countries that have adopted the metric system. It is frequently used in everyday contexts, such as measuring height or small objects, in education, in construction for detailed measurements, and in various fields of science and engineering. It serves as a practical unit bridging smaller units like millimeters and larger units like meters.

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.