- a plane figure having four angles and four sides, as a square.
- a square or quadrangular space or court that is surrounded by a building or buildings, as on a college campus.
- the building or buildings around such a space or court.
- the area shown on one of the standard topographic map sheets published by the U.S. Geological Survey: approximately 17 miles (27 km) north to south and from 11 to 15 miles (17 to 24 km) east to west.
- a plane figure consisting of four points connected by four lines. In a complete quadrangle, six lines connect all pairs of points
- a rectangular courtyard, esp one having buildings on all four sides
- the building surrounding such a courtyard