The Union of Soviet Socialist Republics, a now-dissolved communist superpower that existed from 1922 to 1991.
An acronym from Russian 'Союз Советских Социалистических Республик' (Soyuz Sovetskikh Sotsialisticheskikh Respublik). It's an initialism rather than a traditional word with etymology.
The USSR's collapse in 1991 was so sudden that most people alive then grew up imagining it would last forever—it showed how even massive superpowers can disappear relatively quickly when internal systems fail.
Complete word intelligence in one call. Free tier — 50 lookups/day.