noun
(typography, obsolete) Clipping of quadrat.
(informal) A quadrangle (quadrangular courtyard).
(colloquial, dated) A horse, from colloquial or humorous quadruped specifically for horse.
Something that is quadruple (four times) the usual amount, number, etc.
Clipping of quadruplet (“a set of four; one of a set of four”).
(informal) The quadriceps muscle.
(informal) Quadruplex videotape.
(informal) A quadriplegic person.
A unit of energy equivalent to a quadrillion BTU (10¹⁵ BTU).
A quad bike.
(informal, computer graphics) A quadrilateral.
(informal) A quadcopter.
(informal) A quadrupel beer.
adjective
Quadruple, four times the usual size or quantity.
(paper) Quadrille, marked with squares.
verb
(typography, letterpress typography, transitive, intransitive) To fill spaces in a line of type with quads. Also quad out.
(typography, phototypesetting and digital typesetting, transitive, intransitive) To align text with the left or right margin, or centre it.
(transitive) To twist four individually insulated conductors together as two pairs of twisted wires that are then twisted together.
(intransitive) To ride a quad bike.