Overscript[x, y] is an object that formats as OverscriptBox[x, y].
PermutationProduct[a, b, c] gives the product of permutations a, b, c.
PolynomialQ[expr, var] yields True if expr is a polynomial in var, and yields False otherwise. PolynomialQ[expr, {var_1, ...}] tests whether expr is a polynomial in the var_i.
RecordSeparators is an option for Read, Find, and related functions that specifies the list of strings to be taken as delimiters for records.
Right
(Built-in Mathematica Symbol) Right is a symbol that represents the right-hand side for purposes of alignment and positioning.
RoundingRadius is an option for Rectangle, Framed, and related functions that specifies the radius of the circle to use in rendering rounded corners.
SatisfiabilityInstances[bf] attempts to find a choice of variables that makes the Boolean function bf yield True.SatisfiabilityInstances[expr, {a_1, a_2, ...}] attempts to ...
Scaled
(Built-in Mathematica Symbol) Scaled[{x, y, ...}] gives the position of a graphical object in terms of coordinates scaled to run from 0 to 1 across the whole plot range in each direction. Scaled[{dx, dy, ...
SelectionCreateCell[notebook] copies the contents of the current selection in a notebook into a new cell. SelectionCreateCell[notebook, sel] sets the current selection after ...
SendMail[rules] sends an email message built up from the elements specified in rules.