A yard (abbreviation: yd) is a unit of length in several different systems, including English units, Imperial units, and United States customary units. Its size can vary from system to system. The most commonly used yard today is the international yard, which is equal to 0.9144 meter.

The yard is used as the standard unit of field-length measurement in the American, English, and Canadian games of American football. Other football games such as Soccer once used the yard but now use the metric meter.

A corresponding unit of area is the square yard.

In the context of American and Canadian concrete mixers' loads, a cubic yard is always called simply a yard. A typical marking would indicate that a mixer had a capacity of "11 yards" or "1.5 yards".

Equivalence to other units of length

1 international yard is equal to:

• 3 feet (1 foot is a third of a yard)
• 36 inches
• 0.9144 meter (1 meter is equal to about 1.0936 international yards)

The early yard was divided by the binary method into two, four, eight, and sixteen parts called the half-yard, span, finger, and nail. Two yards are a fathom.

Historical origin

The yard derives its name from the word for a straight branch or rod, although the precise origin of the measure is not definitely known. Some believe it derived from the double cubit, or that it originated from cubic measure, others from its near equivalents, like the length of a stride or pace. One postulate was that the yard was derived from the girth of a person's waist, while another claim held that the measure was invented by Henry I of England as being the distance between the tip of his nose and the end of his thumb. Following the destruction of the British Standard yard in the 1834 fire at the Palace of Westminster, consideration was given to a reproduceable standard should the physical measure be lost again. Accordingly in 1855 an Act was passed defining the standard yard based upon the length of a seconds pendulum. This is 39.1392 inches, and can be derived from the number of beats (86,400) between two meridians of the sun. The 36-inch yard was defined accordingly. The temperature compensated pendulum was to be held in a vacuum at sea level in Greenwich, London to give the length of the standard yard.

See also

• anthropic units
• English unit
• Imperial unit
• Guz, the yard of the Middle East
• United States customary units
• Vara