The term FARM FIELD UNIT consists of three words: ACRE, BALE, and Unit. An ACRE is a unit of area in the imperial and US customary systems of measurement, equal to 4, 840 square yards or 43, 560 square feet. A BALE is a large bundle of hay, straw, or other material, usually bound with twine or wire and used for storage, transportation, and sale. A unit is a single thing, person, or group that is part of a larger whole. In this case, the unit is a measure of the amount of land used for farming. Together, these three words describe a unit of measurement used to measure the size of a farm field.