Definitions of units for area

acre

English unit of area of land. It is equal to one chain (four rods) in width by one furlong in length, or 4840 square yards.

are

Unit of area in metric system (symbol a) used to express agrarian areas. It is equal to 100 square meter.

carucate

An area equal to that which can be ploughed by one eight-oxen team in a single year (also called a plough or carve). Approximately 120 roods.

circular mil

Unit of area, also called cmil, which's equal to the area of a circle with a diameter of one mil (symbol cmil). It is especially used to denote the cross-sectional size of a wire or cable. 1 mil = 0.001 inch. Hence,
1 circular mil = π/4· 10-6 in² = 506.7075 μm².

hectare

Unit of area in metric system (symbol ha), mutiple of are used to express agrarian areas. It is equal to 100 are or 10000 square meter.

rood

Imperial unit of area equal to one quarter of an acre or 40 square rod. It is equivalent to the area of one furlong in length and one rod in width.

square fathom

Imperial unit of area equal to fathom by fathom.

square foot

Imperial unit of area (symbol ft²) derived from foot by foot or 0.09290304 m² exactly.

square furlong

Imperial unit of land measurement equal to furlong by furlong.

square inch

Imperial unit of area (symbol in²) derived from inch by inch or 0.00064516 m² exactly.

square league

Imperial unit of land equal to league by league.

square mil

Unit of area, which's equal to the area of a square with sides of length one mil. It is usually used in specifying the area of the cross section of a wire or cable. 1 mil = 0.001 inch.Hence
1 square mil = (0.001 x 0.0254)² = 1.273 circular mil

square mile

Imperial unit of land equal to statute mile by statute mile.

square meter

SI unit for area (symbol m²) derived from SI base unit meter by meter.

square yard

Imperial unit of area (symbol yd²) derived from yard by yard or 0.83612736 m² exactly.