Patterns are used throughout Mathematica to represent classes of expressions. A simple example of a pattern is the expression f[x_]. This pattern represents the class of ...

ImageSizeMultipliers is an option that specifies how much smaller to render graphics that appear within other constructs.

GenerateConditions is an option for Integrate, Sum, and similar functions that specifies whether explicit conditions on parameters should be generated in the result.

In just one Mathematica command, you can easily specify a calculation that is far too complicated for any computer to do. For example, you could ask for ...

$RootDirectory gives the root directory of your file system.

Heads is an option for functions which use level specifications that specifies whether heads of expressions should be included.

ShowCellLabel is an option for Cell that specifies whether to display the label for a cell.

VertexCount[g] gives a count of the number of vertices in the graph g.VertexCount[g, patt] gives a count of the number of vertices that match the pattern patt.

The standard way in which Mathematica works is to take any expression you give as input, evaluate the expression completely, and then return the result. When you are trying ...

TokenWords is an option for Read and related functions which gives a list of token words to be used to delimit words.