- 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
- sojourn time
- Sokhozki formula
- Sokhozki theorem
- solar active region
- solar activity
- solar calendar
- solar constant
- solar corona
- solar flare
- solar magnetic field
- solar motion
- solar neutrino