AlgebraicUnitQ[a] yields True if a is an algebraic unit, and yields False otherwise.
Alignment is an option which specifies how the contents of a displayed object should be aligned within the available area in the object.
AlignmentPoint is an option which specifies how objects should by default be aligned when they appear in Inset.
All
(Built-in Mathematica Symbol) All is a setting used for certain options. In Part and related functions, All specifies all parts at a particular level.
AllowGroupClose is an option for Cell that specifies whether a cell group can be closed normally.
AllowInlineCells is an option for cells that specifies whether inline cells are permitted within a cell.
AllowReverseGroupClose is an option for Cell that specifies whether a cell group can be reverse closed.
AllowScriptLevelChange is an option for fractions and grids that controls whether certain operators, such as \[Sum], \[Product], and \[Integral], always appear smaller than ...
AlphaChannel[image] returns the alpha channel of image.
AlternatingGroup[n] represents the alternating group of degree n.