noun

• (Philippines) Social Security System
• (US) Selective Service System
• (astronomy) Initialism of super soft source.
• (medicine) Initialism of sick sinus syndrome. [(pathology) An arrhythmia presumably caused by a malfunction of the sinus node, the heart's primary pacemaker.]
• (medicine) Initialism of subclavian steal syndrome. [(medicine) A constellation of signs and symptoms that arise from retrograde (reversed) flow of blood in the vertebral artery or the internal thoracic artery, due to a proximal stenosis and/or occlusion of the subclavian artery.]
• (slang) Initialism of shit, shower, shave. [(countable, uncountable, colloquial, vulgar) Solid excretory product evacuated from the bowels; feces.]
• (computer graphics, art) Initialism of subsurface scattering.