Cork Plug
A 3-D Solid which can stopper a Square, Triangular, or CircularHole. There is an infinite family of such shapes. The one with smallest Volume hasTriangular Cross-Sections and 
; that with the largest Volumeis made using two cuts from the top diameter to the Edge and has Volume 
.
- Supremum Limit
- Surd
- Surface
- Surface Area
- Surface Integral
- Surface of Revolution
- Surface of Section
- Surface Parameterization
- Surgery
- Surjection
- Surjective
- Surprise Examination Paradox
- Surreal Number
- Surrogate
- Surveying Problems
- Survivorship Curve
- Suslin's Theorem
- Suspended Knot
- Suspension
- Suzanne Set
- Suzuki Group
- Swallowtail Catastrophe
- Swastika
- Swastika Curve
- Sweep Signal