Mathematics

• Square (algebra), to multiply a number or other quantity by itself
• Perfect square
• Square matrix
• Square number
• Square root

• Square (geometry), a polygon with four equal sides and angles
• Unit square

• Square wave, a basic kind of non-sinusoidal waveform

Entertainment

• Square (album), an album by Buck 65
• Square (band), a musical trio from Lincoln, Nebraska
• Square Co., former video game company that merged with Enix to become Square Enix
• Square Electronic Arts, joint venture between console video game developers Square and Electronic Arts
• Square Enix, a video game company formed by the merger of Enix and Square
• Square Pictures, a computer-animated film division of Square Co.
• The Square (1994 film), a Chinese documentary
• The Square (2008 film), an Australian film
• The Squares, an English band that formed in 1985

Language

• A modifier adjective, used when describing fielding positions in cricket
• An adjective or noun, used when describing two positions parallel with one another relative to the goal in football (soccer)
• Square character (■), a written character
• Square (slang), an unhip person or a cigarette

Places

• Square Lake, Maine, an unorganized territory in Aroostook County, Maine
• The Square, a common name for public squares
• Tiananmen Square in Beijing, China, the largest open urban square in the world
• Times Square, a popular landmark in New York City
• Town square or Market square, an open area commonly found in the heart of a traditional town
• Trafalgar Square in London, England

Other

• An astrological aspect of 90 degrees
• Broken square
• Carpentry square, a tool
• Infantry square
• Square (area), an Imperial unit of floor area and other construction materials
• Square (cipher), a cryptographic block cipher
• Square division, a form of military organization
• Square rig, a type of sail and rigging arrangement
• SQUARE methodology, a CERT SEE developed methodology for security requirements engineering