There’s the furlong, for example, derived from the Old English for furrow, furh, and long, lang, which measures length, not area, and refers to the distance that could be covered by a team of oxen before they needed to rest (and which is now standardised as 201 metres or 660 feet). Furlongs were used to calculate the day-work unit of the aker, from the Old English aecer, meaning ‘open field’ (and from which we get the modern acre of 4,047 square metres or 43,560 square feet).
