- Foot is also the name of a body part. See foot.
Foot is a unit of measurement of length (how long something is). It is one of the U.S. customary and imperial units. Sometimes it is called a "U.S. foot" because it is used most often in the United States.[source?] It is called a foot, because it is about the size of a man's foot. This measurement is widely used in America, Britain, Ireland, and other countries of the former British Empire.
In some countries, people often measure height (how tall a person is) in feet and inches. If a person is "five foot eleven", this means that person is 5 feet and 11 inches, or about 180 centimeters. The height is written 5' 11".
The abbreviation for (the short way of writing) "foot" is ' or ft.