Masking
(Built-in Mathematica Symbol) Masking is an option for various image analysis and processing functions that specifies on which regions they should operate.
MaxPlotPoints is an option for plotting functions like ArrayPlot and ListPlot3D that specifies the maximum number of points that will explicitly be included in the output.
NullRecords is an option for Read and related functions which specifies whether null records should be taken to exist between repeated record separators.
NumberMultiplier is an option for NumberForm and related functions which gives the string to use as a multiplication sign in scientific notation.
NumberPadding is an option for NumberForm and related functions which gives strings to use as padding on the left- and right-hand sides of numbers.
NumberPoint is an option for NumberForm and related functions which gives the string to use as a decimal point.
OutputStream["name", n] is an object that represents an output stream for functions such as Write.
ReadProtected is an attribute that prevents values associated with a symbol from being seen.
ReleaseHold[expr] removes Hold, HoldForm, HoldPattern, and HoldComplete in expr.
RotationAction is an option for three-dimensional graphics functions that specifies how to render 3D objects when they are interactively rotated.