Foot (unit)
unit of length
The foot (standard symbol: ft) is a unit of length in the British imperial and United States customary systems of measurement. The prime symbol, ′, is commonly used to represent the foot. In both customary and imperial units, one foot comprises 12 inches, and one yard comprises three feet. Since an international agreement in 1959, the foot is exactly 0.3048 meters, by definition. The most common plural of foot is feet. However, the singular form may be used like a plural when it is preceded by a number, as in "that man is six foot tall". Footage is the term used informally for a length expressed in feet.
Historically, the "foot" was a part of many local systems of units, including the Greek, Roman, Chinese, French, and English systems. It varied in length from country to country, from city to city, and sometimes from trade to trade. Its length was usually between 250 mm (9.8 in) and 335 mm (13.2 in) and was generally, but not always, subdivided into twelve inches or 16 digits.
The public source identifies “Foot (unit)” as unit of length. This brief keeps that definition visible, then builds a research path around Foot, unit and length.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 19, 2026. The linked authority identifier is Q3710. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1959.
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This entry incorporates text from “Foot (unit)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.