(quantum mechanics) The quantum theory of the gravitational field. / (quantum mechanics) The study of quantum fields in curved spacetime.

(mathematics) a polynomial equation of the second degree.

(simile) To appear to be exactly what one is.

A dance originating in the mid-1700s with four couples forming a square, rather much like the modern square dance. / The music for this dance.

(intransitive) To dance the quadrille.

Quadrille ruled graph paper, quad paper.

A square tiling of the plane.

(mathematics) The formula x=(-b±√)/(2a) for finding roots of the quadratic equation.

(mathematics) Any function whose value is the solution of a quadratic polynomial

A period of 4 years, particularly (historical) the sets of four years in the ancient Egyptian and Greek calendars.