- free probability
- free probability theory
- free problem
- free product
- free product group
- free quantization
- free random walk
- free resolution
- free ring
- free semigroup
- free set
- free sheaf
- free statistic
- free streamline theory
- free subgroup
- free subscript
- free substitution
- free surface
- free system
- free term
- free tree
- free trivector
- free ultrafilter
- free union
- free universal algebra