DependentVariables is an option which specifies the list of all objects that should be considered as dependent variables in equations that have been supplied.
FrontEndEventActions is an option for the notebook front end that gives a list of actions to perform when specified user-interface events occur.
LinkPatterns[link] gives a list of the patterns for which definitions were set up when the external program associated with the specified MathLink connection was installed.
NonConstants is an option for D which gives a list of objects to be taken to depend implicitly on the differentiation variables.
NotebookInformation[] gives a list of properties of the current evaluation notebook.NotebookInformation[notebook] gives a list of properties for the specified notebook.
SpellingOptions -> {opt_1 -> val_1, opt_2 -> val_2, ...} is an option for notebooks that specifies settings for spell checking.
Verbatim[expr] represents expr in pattern matching, requiring that expr be matched exactly as it appears, with no substitutions for blanks or other transformations.
$CharacterEncodings gives the list of character encodings that can be used.
$ExportFormats gives a list of export formats currently supported in your Mathematica system.
$ImportFormats gives a list of import formats currently supported in your Mathematica system.