ChessboardDistance[u, v] gives the chessboard, Chebyshev, or sup norm distance between vectors u and v.
CircleDot[x, y, ...] displays as x\[CircleDot]y\[CircleDot]....
ClosingAutoSave is an option for notebooks that specifies whether a notebook is automatically saved when it is closed.
ContextToFileName["context"] gives the string specifying the file name that is by convention associated with a particular context.
CounterAssignments is an option for selections that sets the value of a specified counter.
CounterIncrements is an option for selections that specifies whether the value of a specified counter is incremented by one.
CupCap
(Built-in Mathematica Symbol) CupCap[x, y, ...] displays as x \[CupCap] y \[CupCap] ....
Cup
(Built-in Mathematica Symbol) Cup[x, y, ...] displays as x\[Cup]y\[Cup]....
Cyan
(Built-in Mathematica Symbol) Cyan represents the color cyan in graphics or style specifications.
DefaultFontProperties is a global option that specifies various properties of a font family, such as its character encoding and whether it is monospaced.