- s.s.complex (= semisimplicial complex)
- S-set
- S-shaped curve
- S-shaped distribution
- S-signature
- S-space (= Schwartz space)
- SSS theorem
- S-structure
- SST (= shortest service time)
- s-system
- stability
- * -stability
- stability analysis
- stability condition
- stability criterion
- stability factor
- stability group
- stability index
- stability in finite time
- stability in large
- stability matrix
- stability number
- stability of a computational process
- stability of a control system
- stability of a equilibrium