RecordSeparators is an option for Read, Find, and related functions that specifies the list of strings to be taken as delimiters for records.
Regularization is an option for Sum and Product that specifies what type of regularization to use.
Return
(Built-in Mathematica Symbol) Return[expr] returns the value expr from a function. Return[] returns the value Null.
RotationAction is an option for three-dimensional graphics functions that specifies how to render 3D objects when they are interactively rotated.
Run
(Built-in Mathematica Symbol) Run[expr_1, expr_2, ...] generates the printed form of the expressions expr_i, separated by spaces, and runs it as an external operating system command.
SaveDefinitions is an option to Manipulate and related functions that specifies whether current definitions relevant for the evaluation of the expression being manipulated ...
ScriptSizeMultipliers is an option for Style that specifies how much smaller to render each successive level of subscripts, etc.
SelectionCreateCell[notebook] copies the contents of the current selection in a notebook into a new cell. SelectionCreateCell[notebook, sel] sets the current selection after ...
SetSharedVariable[s_1, s_2, ...] declares the symbols s_i as shared variables whose values are synchronized among all parallel kernels.
SetStreamPosition[stream, n] sets the current point in an open stream.