Acre (noun)

1. A unit of area in the U.S. Customary System, equal to 43,560 square feet (4,047 square meters).
2. A piece of land containing this unit of area.

Origin:

Middle english, from old english æcer, from latin ager field, from agere to drive, do; akin to greek agros field.

Examples:

1. The property is five acres.
2. The farmer cultivates ten acres of corn.
3. The park is fifty acres in size.
4. The land is being sold for $10,000 per acre.
5. They measured the size of the garden in acres.