A Soviet Socialist Republic; a constituent republic of the USSR.

Secondary surveillance radar used for aircraft identification and tracking.

A solid-state relay, an electronic switching device.

U.S. Navy hull code for a radar picket submarine.

A special service requirement or special service request.

The sum of squared residuals in statistical modeling.

Server-side rendering of web pages.

Sustained silent reading, a classroom reading practice.

A Small Ships Register, typically a national small-craft registry.

Special support and reconnaissance, a military mission profile.