- Sobolev inequalities
- Sobolev inequality
- Sobolev space
- Sobolev spaces
- social-cybernetics
- social dilemma
- social welfare function
- social welfare function
- socle of a ring
- socle of group
- socle of module
- Soddy circle
- soft classification space
- soft landing
- soft sheaf
- software
- software development tool
- software engineering
- software life cycle
- software maintenance
- software package of group-theoretic algorithms
- software radio
- software reliability
- software testing
- software useful degree