CellGroupingRules is an option for cells that specifies the rules used for grouping a cell.
Character represents a single character in Read.
ChartElements is an option to charting functions such as BarChart that specifies the graphics to use as the basis for bars or other chart elements.
ChartStyle is an option for charting functions that specifies styles in which chart elements should be drawn.
CircleTimes[x] displays as \[CircleTimes]x.CircleTimes[x, y, ...] displays as x\[CircleTimes]y\[CircleTimes]....
Colon
(Built-in Mathematica Symbol) Colon[x, y, ...] displays as x \[Colon] y \[Colon] ....
Congruent[x, y, ...] displays as x \[Congruent] y \[Congruent] ....
Contexts[] gives a list of all contexts. Contexts["string"] gives a list of the contexts that match the string.
ContourStyle is an option for contour plots that specifies the style in which contour lines or surfaces should be drawn.
Convergents[list] gives a list of the convergents corresponding to the continued fraction terms list.Convergents[x, n] gives the first n convergents for a number ...