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 ????? (agros). -Wikipedia
An acre is 43,560 Square Feet, but why?
Here is a great answer from YourHub.com:
Neolithic Megalithic Measurements
By about 5,000 BC, all sorts of things were being invented, not least among them a standardized unit of measurement. This unit of measurement was based on the circumference of the Earth.
From experiments and observation, people understood that the earth was a sphere and that it rotated on its axis. Rather than measuring the time of rotation based on either the moon or the sun (the sun and moon rise and set at different times each day and are not constant), people measured a “day” by the time it took for a star to return to its original position in the sky: stars do not “move” in the same observable way that the sun and moon do.
Well, as soon as it was decided that stars were better to measure the rotation of the earth by, it was observed that the earth rotated around the sun: a star would not return to its original position for 366 days! Thus, in original geometry, the circle had 366 degrees, not 360 (it was shortened by 6 degrees by the Sumerians to make math easier).
A person could stand outside at night and divide the horizon into 366 degrees, and then observe the time it took for a star to pass between that one degree by use of a pendulum. If the pendulum’s length was “correct” (a standard size), it would take 366 swings for a star to pass between the two degrees on the horizon. The star they used was Venus (actually a planet), and because Venus had a changing speed during the year, they calibrated their pendulums on the day of the year when Venus moved the slowest.
The length of this pendulum was the foundation of all modern units of measurement, and is known to archeologists as the “Megalithic Yard.” The Megalithic Yard is similar in size to the Meter, and measures roughly 2.722 Feet (82.966 Centimeters). The Megalithic Yard was divided into 40 units, called “Megalithic Inches.”
By making a cube with each side the length of 1/10 of these Megalithic Yards (4 MI) and filling the cube, standardized units of volume was developed. This unit of volume is now called the Pint. A cube with a length of 8 MI is called the Gallon. A cube with a length of 16 MI is called the Bushel.
If the same volume is filled with water or seed, units of weight can be found. Grain (Barley seed was used by the ancients) occupies about 125% of the volume of water when placed in a cubical container. When a Pint is filled with barley, it weighs one pound. However, some of the ancients filled the Pint with water, and called it a pound. The difference between a Pound Avoirdupois and a Pound Troy is thus explained.
When 40 MY are squared, the resulting area is known as the Irish Acre (23,520 square feet). 75 MY x 100 MY equals the Scottish Acre.
A Sumerian Wheel of 360 Degrees
So where does the modern acre come in? As the megalithic peoples based all numbers off of the 366 degrees of the earth’s rotation, the Sumerians based all their numbers off 360 degrees of the earth’s rotation.
6 MY described a “Megalithic Rod.” When an area is made measuring 4 MR x 40 MR, you get the modern Acre. This can also be described as being 16 sections measuring 360 MY in area. The modern acre originated from a time after the Sumerian improvement of rounding down from 366 degrees to 360 degrees.
Further evidence of the modern acre being the result of Sumerian improvement can be seen in how the modern acre of 43560 square Feet may be divided evenly into 121 sections of 360 square feet: 11 sections of 360 feet is 3,960 Feet, and 11 sections of 3,960 feet is an Acre.
11 sections of 11 sections seems arbitrary, but many units of area are designed on this number: the square Mile may be divided into 121 (11 x 11) sections of 230,400 square Feet, with each section’s side equal to 1/11 of a mile (480 Feet). These 121 pieces may be divided into 640 sections of 360 feet, similar to how an American Square Mile is divided into 640 Sections (each section equaling an acre).
Modern units of measurement are based on older, Sumerian-influenced methods of measurements.
Though the Sumerian-influenced descendants of the megalithic peoples attempted to simplify the megalithic accounting, they still used the same methods of dividing land into sections of 360 square feet.
French, American and Minoan Wheels
The ease of the Sumerian system was eventually improved by bringing it into conformity with a base-ten system. The French are usually given credit for this “metric” system. The Meter was developed using the Sumerian 360 degree circle as a starting point. Thus, the metric system is based off of the Sumerian improvement to the megalithic system.
Thomas Jefferson, like the French when they developed the metric system, wanted to improve the Sumerian system by bringing it into conformity with a base-10 system. He attempted to introduce to the newly formed United States his better form of measurement based on a 360 degree circle. But, unlike the Meter in France, the Jeffersonian Units of measurement never caught on.
Was Thomas Jefferson’s improvement new? 1,000 Jefferson Feet (Jefferson’s units were to be referred to as Jefferson Feet, Jefferson Miles, etc.), was set to equal 360 MY. However, 1,000 Minoan feet had equaled the same distance for thousands of years before Jefferson: the ancient Minoans had the same idea as Jefferson and ought to be given credit for bringing the Sumerian improvement into a base-ten system.
1) Alexander Thom, including the Megalithic Sites in Britain (1955), Megalithic Sites in Britain (1967), Megalithic Sites in Britain (1968) and A Statistical Examiniation of Megalithic Remains in Britain and Brittany (1978).
2) D. C. Heggie, Megalithic Science (1981).
3) J.W. Graham, Palaces of Crete (1962)
4) Christopher Knight, Civilization One. A good review of the literature can be found in this book, but, while this book serves as a good review, the reader is cautioned: Knight’s ability to succinctly compile the vast body of archeological research is amazing, but the last few chapters of his book (which resort to explaining the knowledge of the ancients as being due not to their own ingenuity, but through the actions of angels and other daemons) is highly questionable.