Code
A code is a set of 
-tuples of elements (``Words'') taken from an Alphabet.
- Characteristic (Euler)
- Characteristic Factor
- Characteristic (Field)
- Characteristic Function
- Squareful
- Square Gyrobicupola
- Square Integrable
- Square Knot
- Square Matrix
- Square Number
- Square Orthobicupola
- Square Packing
- Square Polyomino
- Square Pyramid
- Square Pyramidal Number
- Square Quadrants
- Square Root
- Square Root Inequality
- Square Root Method
- Square Triangular Number
- Square Wave
- Squaring
- Squeezing Theorem
- s-Run
- S-Signature