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Acre

[ey-ker]

Acre, state (1990 est. pop. 1,125,100), 58,915 sq mi (152,590 sq km), W Brazil, on the borders of Peru and Bolivia. Rio Branco is the capital.

The Columbia Electronic Encyclopedia Copyright © 2004.
Licensed from Columbia University Press

Acre

Acre, Israel: see Akko.

The Columbia Electronic Encyclopedia Copyright © 2004.
Licensed from Columbia University Press

acre

acre, measure of land area used in the English units of measurement. The acre was originally the area a yoke of oxen could plow in a day and therefore differed in size from one locality to another. It is now fixed as 10 square chains or 160 square rods, i.e., 4,840 sq yd, 43,560 sq ft, or 1/640 sq mi. It is equal to about .4047 of a hectare or 4,046.9 sq m.

The Columbia Electronic Encyclopedia Copyright © 2004.
Licensed from Columbia University Press

&ayn;Akko

or Acre

Seaport town (pop., 2004 est.: 45,600), northwestern Israel. First mentioned in an Egyptian text from the 19th century BC, it was long a Canaanite and Phoenician city. After its conquest by Alexander the Great (336 BC), it was a Greek polity (called Philadelphus), and for several centuries it was part of the Roman Republic and Empire. The city was being ruled by the Turkish Seljūq dynasty when the Crusaders captured it in 1104 and renamed it St. Jean d'Acre. It was the last capital of the Crusades, falling in 1291. Except for brief intervals, it was under the rule of the Ottoman Empire from 1516 until British forces took it in 1918. It was part of Palestine under the British mandate and became part of Israel in 1948, when most of its Arab inhabitants fled. Notable structures include the Great Mosque and the Crypt of St. John. It is the burial place of Bahāhamzah Ullāh, the founder of the Bahāhamzahī faith.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.

Acre

The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre.

One international acre is equal 4046.8564224 m². One U.S. survey acre is equal to m² = 4046.8726098 m².

One acre comprises 4,840 square yards or 43,560 square feet (which can be easily remembered as 44,000 square feet, less 1%). Because of alternative definitions of a yard or a foot, the exact size of an acre also varies slightly. Originally, an acre was a selion of land one furlong (660 ft) long and one chain (66 ft) wide. However, an acre is a measure of area, and has no particular width, length or shape.

The acre is often used to express areas of land. In the metric system, the hectare is commonly used for the same purpose. An acre is approximately 40% of a hectare.

One acre is 90.75 yards of a 53.33-yard-wide American football field. The full field, including the end zones, covers approximately 1.32 acres.

International acre

In 1958, the United States and countries of the Commonwealth of Nations defined the length of the international yard to be 0.9144 meters. Consequently, the international acre is exactly 4046.8564224 square meters.

United States survey acre

The United States survey acre is approximately 4046.873 square meters; its exact value (m²) is based on an inch defined by 1 meter = 39.37 inches exactly, as established by the Mendenhall Order. It is the standard acre in the United States, but the fractional difference from the international acre is only 40 millionths, or 4 ten-thousandths of one percent.

Equivalence to other units of area

1 international acre is equal to the following metric units:

4046.8564224 square meters
0.40468564224 hectare

1 United States survey acre is equal to:

4046.87261 square meters
0.404687261 hectare

1 acre (both variants) is equal to the following customary units:

66 feet × 660 feet (43,560 square feet)
1 chain x 10 chains (1-chain = 66 feet or 22 yards or 4 rods)
1 acre is approximately 208.71 feet x 208.71 feet (square)
4840 square yards
160 perches. A perch is equal to a square rod (1 square rod is 0.00625 acre)
10 square chains
4 roods
A chain by a furlong (chain 22 yards, furlong 220 yards)
0.0015625 square mile (1 square mile is equal to 640 acres)

1 international acre is equal to the following Indian unit:

100 Indian cents (1 cent is equal to 0.01 acre)

Historical origin

The word "acre" is derived from Old English æcer (originally meaning "open field", cognate to west coast Norwegian language "ækre" and Swedish "åker", German Acker, Latin ager and Greek αγρος (agros).

The acre was approximately the amount of land tillable by one man behind an ox in one day. This explains one definition as the area of a rectangle with sides of length one chain and one furlong. A long narrow strip of land is more efficient to plough than a square plot, since the plough does not have to be turned so often. The word "furlong" itself derives from the fact that it is one furrow long.

Before the enactment of the metric system, many countries in Europe used their own official acres. These were differently sized in different countries, for instance, the historical French acre was 4221 square metres, whereas in Germany as many variants of "acre" existed as there were German states.

Statutory values for the acre were enacted in England by acts of:

Edward I,
Edward III,
Henry VIII,
George IV and
Victoria – the British Weights and Measures Act of 1878 defined it as containing 4,840 square yards.

Historically, the size of farms and landed estates in the United Kingdom was usually expressed in acres (or acres, roods, and perches), even if the number of acres was so large that it might conveniently have been expressed in square miles. For example, a certain landowner might have been said to own 32,000 acres of land, not 50 square miles of land.

Customary acre

The customary acre was a measure of roughly similar size to the acre described above, but was subject to considerable local variation. However, there were more ancient measures that were also used, including carucates, virgates, bovates, nooks, and farundells or farthingales. These may have been multiples of the customary acre, rather than the statute acre.