SSC stands for Safe, Sane, and Consensual, a framework for negotiating and evaluating BDSM play that requires everyone involved to be physically safe, in a sound state of mind, and giving genuine consent.
Popularized in the 1980s by the gay leather community and later adopted widely across BDSM, SSC was an early attempt to draw a clear ethical line around kink at a time when it was heavily stigmatized. Some practitioners now prefer RACK or PRICK because they find 'safe' too absolute for activities that carry inherent risk.
Worth knowing: SSC is itself a safety framework, so using it means making sure all parties are informed, capable of consenting, and free to withdraw at any point.
Also called: RACK (Risk-Aware Consensual Kink), PRICK (Personal Responsibility In Consensual Kink), CCC (Caring, Consensual, Consensual), consent frameworks, BDSM principles