Quad

Quad is a latin prefix meaning four. (Tetra is the Greek equivalent).

The word quad can mean a number of things:

• A prefix meaning "four"
• A quad bike - see All-terrain vehicle
• In architecture, the abbreviation for a quadrangle
• A play by Samuel Beckett; see Quad (play)
• A telecommunication term
• The Quadrangle Club, one of the eleven eating clubs at Princeton University
• In Plane Geometry, a Quadrilateral is a four sided figure
• In studies of animal locomotion and walking machines, a quadruped is a four-legged creature or mechanism
• The name of a well reputed British manufacturer of electronic amplifiers, tuners and loudspeakers mainly for the high-end domestic market
• The short form of a muscle's name: the quadriceps
• An unit of energy (short for quadrillion) defined as 10¹⁵ BTUs (about 1.055 &times 10¹⁸ J)
• In computer science, a seldom-used unit of information defined as four eight-bit bytes.
• One 1000th part of the fictional (Star Trek) unit of a kiloquad

In the language used by trade negotiators, the 'quad' are the countries of the United States, Japan and Canada, plus the European Union. These four economies are responsible for around 61% of world imports by value, and 71% of world exports, and so they have considerable clout within the World Trade Organisation.