(physics) The antiquark corresponding to the strange quark.

(physics) The antiquark corresponding to the charm quark.

(physics) The antiquark corresponding to the up quark.

(physics) the antiquark corresponding to the top quark.

(physics) The antiquark corresponding to the bottom quark.

Printed to a sufficient visual standard to be sent as a letter.

Describing printed material that is good enough for preliminary use but not good enough to be sent out. Now somewhat obsolete due to advances in printer technology; at one time many printers offered a choice between fast draft-quality and better appearing letter-quality.

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.