Quad

Quad as a word or prefix usually means four. It may refer to:

Government

 * Quadrilateral Security Dialogue, a strategic security dialogue between Australia, India, Japan, and the United States
 * Quadrilateral group, an informal group that includes the trade spokesmen of the United States, Japan, Canada, and the European Union
 * Quad Cities, a group of five cities straddling the boundary between the U.S. states of Iowa and Illinois
 * The "Quad", the senior members of the Cameron–Clegg coalition government in the United Kingdom from 2010 to 2015

Art and entertainment

 * Matthias Quad (1557–1613), engraver and cartographer
 * Quad (film), 2015
 * Quad (music), a musical project by Gary Ramon
 * Quad (play), by Samuel Beckett
 * The Quad (TV series), 2017
 * Quad (arts centre), in Derby, United Kingdom
 * Quad Cinema, art house in New York City, New York
 * Quad (company), formerly Quad/Graphics, an international marketing company
 * Quadruple combination, the four books that comprise the canon of the LDS church

Medicine and anatomy

 * Quadriplegic, a person paralyzed in all four limbs
 * Quadriceps femoris, a large leg muscle group
 * Quadruplets, four children from a multiple birth

Sports

 * Quad (figure skating), a figure skating jump with four revolutions
 * Quad scull, a boat configuration of four rowers
 * Quad skates, roller skates with two wheels on each of two axles
 * Quad, one of the divisions in wheelchair tennis
 * Quadruple-double, a statistical accomplishment in basketball
 * Quadrennium, the 4-year training cycle between Olympic games

Transportation

 * Quad bike or all-terrain vehicle, a vehicle that travels on low-pressure tires
 * Quad, a tandem bicycle with four seats
 * Quadracycle, a four-wheeled human-powered land vehicle
 * Jeffery Quad, a four-wheel drive truck
 * Quadcopter, a four-rotor helicopter
 * Quad, a chairlift in skiing which carries four persons
 * Quad, or railroad speeder, a motorized vehicle used for maintenance on railroads
 * Quad (rocket), an autonomous rocket by Armadillo Aerospace

Technology

 * QUAD (cipher), a stream cipher
 * QUaD, a microwave telescope at the South Pole
 * Quad antenna, a directional antenna
 * Quad Electroacoustics, a British manufacturer of audio equipment
 * Quadraphonic sound, four-channel sound
 * Quadruplex videotape, video tape format
 * Quad Flat Package, a type of package for surface mounted integrated circuit
 * Star quad cable, four insulated conductors twisted together

Other uses

 * Quad (unit), unit of energy, short for quadrillion, 1015 BTU
 * Quadrangle (architecture), a space or courtyard bordered by buildings
 * Quad (geography), a United States Geological Survey topographical map
 * Quad (typography), a spacer used in letterpress type
 * Quadrilateral, in geometry
 * Quad poster, a common UK size of film poster
 * Quadrat, in ecology, a small study area or a frame used to define it
 * Quadrupel, a Belgian beer
 * The Quad Casino (now The Linq), on the Las Vegas Strip
 * Four-of-a-kind in poker
 * Sako Quad, a Finnish bolt-action rifle