A numerical description of the flatness or roughness of a surface, especially an optical or machined surface.

(of a sound system) Employing four independent channels or speakers.

(mathematics) A type of average, calculated as the square root of the mean of the squares, ie. Q=√x_1²+x_2²+...+x_n²/n.

plural of quantum cascade laser

One who qualifies for something, especially a contestant who qualifies for a stage in a competition. / A preliminary stage of a competition.

(computing, Internet) An Internet domain name that identifies a computer.

(quantum mechanics) Any phenomenon that arises when a quantity that becomes zero according to classical physics acquires a finite value when quantum rules are utilized.

(quantum mechanics) the study of the effects of the laws of quantum mechanics on the propagation and absorption of sound

(quantum mechanics) The field concerned with the interaction of radiation and matter, and on the effects of quantum mechanics on the behaviour of electrons.

(chemistry, physics) the application of quantum mechanics to chemical problems