Morgen
A morgen was a unit of measurement of land area in Germany, the Netherlands, Poland and the Dutch colonies, including South Africa and Taiwan. The size of a morgen varies from 1⁄2 to 2 1⁄2 acres, which equals approximately 0.2 to 1 hectare. It was also used in old Prussia, in the Balkans, Norway and Denmark, where it was equal to about two-thirds of an acre (0.27 ha).
The word is usually taken to be the same as the German and Dutch word for "morning". Similarly to the Imperial acre, it was approximately the amount of land tillable by one man behind an ox in the morning hours of a day. The morgen was commonly set at about 60–70% of the tagwerk (literally "day work") referring to a full day of ploughing. In 1869, the North German Confederation fixed the morgen at a quarter hectare (i.e. 2500 square meters) but in modern times most farmland work is measured in full hectares. The next lower measurement unit was the German "rute" or Imperial rod but the metric rod length of 5 metres never became popular. The morgen is still used in Taiwan today, called "kah"; 1 kah is roughly 2 acres or 9,000 m2.
The following table shows an excerpt of morgen sizes as used in Germany - some morgen were used in a wider area and so they had proper names. It is noteworthy that the actual area of a morgen was considerably larger in fertile areas of Germany, or in regions where flat terrain prevails, presumably facilitating tilling. The next lower measurement unit to a morgen was usually in "Quadratruten" square rods.
...
Wikipedia