The ſ character, as distinct from the short s (which is the s character).

Abbreviation of Song of Solomon.

signal-to-noise ratio / signal-to-noise / Initialism of serial number.

(geology, seismology) A transverse, shear wave, such as that produced by an earthquake. Movement is transverse to the direction of propagation and is a body wave.

(organic chemistry) transoid

(organic chemistry) cisoid

(physics) An ultrahigh radio frequency, one within the range of 1,550 to 5,200 MHz.

(Canada, military) Non-serviceable, broken, needing repair. Official abbreviation of non-serviceable, used on tags attached to equipment needing servicing.

(nautical) Initialism of nuclear ship.: a ship's prefix for shipnames of nuclear-powered ships

Alternative form of 1950s