Oxgang
Origin
From Middle English oxegang, from Old English oxangang ("an eighth of a plough-land, a hide"), equivalent to ox + gang.
Usage notes
Land was normally ploughed with a team of eight oxen. An oxgang is roughly 13-15 acres, an eighth share of the land ploughed by an ox team in a day. The area differed by locality. In Scottish law it was about 13 acres - but this was also dependent on soil quality.