- triomino
- triorthogonal
- triorthogonal code
- triorthogonal system of surfaces
- tripartite curve
- triplanar point
- triple
- tripleability
- tripleable
- tripleable functor
- tripleableness
- triple curve
- triple cylinder
- triple-diagonal matrix
- triple-free set
- triple integral
- triple integral equation
- triple Jacobi product
- triple line
- triplen
- triple of points
- triple of vectors
- triple point
- triple pole
- triple product