ChoiceDialog[expr] puts up a standard choice dialog that displays expr together with OK and Cancel buttons, and returns True if OK is clicked and False if Cancel is ...
ClearAttributes[s, attr] removes attr from the list of attributes of the symbol s.
Closing
(Built-in Mathematica Symbol) Closing[image, ker] gives the morphological closing of image with respect to the structuring element ker.Closing[image, r] gives the closing with respect to a range r square.
ColorCombine[{image_1, image_2, ...}] creates a multichannel image by combining the sequence of channels in the image_i. ColorCombine[{image_1, image_2, ...}, colorspace] ...
ColorSeparate[image] gives a list of single-channel images corresponding to each of the color channels in image.ColorSeparate[image, colorspace] gives a list of images ...
ColumnWidths is an option for the low-level function GridBox which specifies the widths to use for columns.
Compiled is an option for various numerical and plotting functions which specifies whether the expressions they work with should automatically be compiled.
Constants is an option for Dt which gives a list of objects to be taken as constants.
ContentSelectable is an option to constructs such as Inset, Graphics, and GraphicsGroup that specifies whether and how content within them should be selectable.
ControllerLinking is an option for Manipulate, Graphics3D, Plot3D, and related functions that specifies whether to allow interactive control by external controllers.