Not quite. An acre is the area that oxen could plough in a day. A furlong is the distance that they could pull the plough without resting. As turning an ox-dra

Not quite. An acre is the area that oxen could plough in a day. A furlong is the distance that they could pull the plough without resting. As turning an ox-drawn plough is difficult, they would plough the maximum straight distance before turning around, resulting in long, narrow fields a furlong in length. An acre of ploughed land, which was standardised in the late 13th century at 40 rods (a furlong) long and 4 rods (a chain) wide, would contain about 80 furrows- so the oxen would have pulled the plough 10 miles in a day. As for the chain, it's actually a slightly newer unit, equal to 4 rods or a tenth of a furlong (or 66 feet, the length of a cricket pitch)- so an acre is 10 square chains. It was introduced in the early 17th century, when iron was cheap enough that surveyors could measure land with iron chains rather than wooden rods. It's still used in distance markers on British railways.