The word
acre is derived from the
Norman, attested for the first time in 1006 in a text from
Fécamp with the meaning of "agrarian measure".
Acre dates back to the old Scandinavian
akr "cultivated field, ploughed land" which is perpetuated in
Icelandic and the
Faroese "field (wheat)",
Norwegian and
Swedish ,
Danish "field",
cognate with
German ,
Dutch ,
Latin ,
Sanskrit , and
Greek (). In English, an obsolete variant spelling was
aker. According to the
Act on the Composition of Yards and Perches, dating from around 1300, an acre is "40
perches
rods] in length and four in breadth", meaning 220 yards by 22 yards. As detailed in the diagram, an acre was roughly the amount of land tillable by a yoke of oxen in one day. Before the introduction of the
metric system, many countries in Europe used their own official "acres" (with other names). In France, the traditional unit of area was the
arpent carré, a measure based on the Roman system of land measurement. The was used only in
Normandy (and neighbouring places outside its traditional borders), but its value varied greatly across Normandy, ranging from 3,632 to 9,725 square metres, with 8,172 square metres being the most frequent value. But inside the same of Normandy, for instance in
pays de Caux, the farmers (still in the 20th century) made the difference between the (68 ares, 66 centiares) and the (56 to 65 ca). The Normandy was usually divided in 4 (
roods) and 160 square , like the English acre. The Normandy was equal to 1.6 , the unit of area more commonly used in Northern France outside of Normandy. In Canada, the Paris used in
Quebec before the metric system was adopted is sometimes called "French acre" in English, even though the Paris and the Normandy were two very different units of area in ancient France (the Paris became the unit of area of French Canada, whereas the Normandy was never used in French Canada). In Germany, the Netherlands, and Eastern Europe the traditional unit of area was . Like the acre, the
morgen was a unit of ploughland, representing a strip that could be ploughed by one man and an ox or horse in a morning. There were many variants of the
morgen, differing between the different German territories, ranging from . It was also used in
Old Prussia, in the Balkans,
Norway, and
Denmark, where it was equal to about . Statutory values for the acre were enacted in England, and subsequently the United Kingdom, by acts of: •
Edward I •
Edward III •
Henry VIII •
George IV •
Queen Victoria – the British
Weights and Measures Act 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. The acre is related to the square mile, with 640 acres making up one square mile. One mile is 5280 feet (1760 yards). In western Canada and the western United States, divisions of land area were typically based on the square mile, and fractions thereof. If the square mile is divided into quarters, each quarter has a side length of mile (880 yards) and is square mile in area, or 160 acres. These subunits are typically then again divided into quarters, with each side being mile long, and being of a square mile in area, or 40 acres. In the United States, farmland was typically divided as such, and the phrase "the back 40" refers to the 40-acre parcel to the back of the farm. Most of the
Canadian Prairie Provinces and the US Midwest are on square-mile grids for surveying purposes. == Legacy units ==