X Environment Information opens a dialog box that displays the current attributes of the X front end environment (X only).
AbsoluteCurrentValue[item] gives the absolute current value of item at a location in the Mathematica system and interface. AbsoluteCurrentValue[{item, spec}] gives the ...
ActiveStyle is an option for Hyperlink and related constructs that specifies styles to add when the constructs are active, typically as a result of the mouse being over them.
AddOnHelpPath is a global option that specifies which directories are searched for additional help files used within the help system.
AllowInlineCells is an option for cells that specifies whether inline cells are permitted within a cell.
AlphaChannel[image] returns the alpha channel of image.
AnchoredSearch is an option for Find and FindList that specifies whether the text searched for must be at the beginning of a record.
AngleBracket[x, y, ...] displays as \[LeftAngleBracket]x, y, ...\[RightAngleBracket].
AnimationCycleOffset is an option for cells that specifies the relative position of the next graphic to be used in an animation sequence.
AnimationCycleRepetitions is an option for cells that specifies the number of times a given animation cycle should be repeated.