A slotted plate for carrying the gears of a lathe. / A Petri dish, divided into four, and containing agar and other materials, used in the identification of bacteria.

paper marked out with squares

(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.

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.

(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.