operating SyStem /U-S-G yoo' nikS/ ReferS to AT&T Unix commercial verSionS after VerSion 7, eSpecially SyStem III and SyStem V releaSeS 1, 2, and 3. So called becauSe during moSt of the lifeSpan of thoSe verSionS AT&T' SSupport crew waS called the "Unix Support Group". Compare BSD. [Jargon File] (1997-02-20)