- special linear group
- special model
- special orthogonal group
- special perturbation
- special p-group
- special plot software
- special point of locus
- special radical
- special semimartingale
- special situation
- special solution
- special subclass
- special topic chart
- special triangular matrix
- special unitary group
- special valued lattice-ordered group
- special variation
- special Whitehead group
- species difference
- species difference
- species Lotka-Volterra systems
- specification
- specific combining ability
- specificity
- specified arrangement