$DisplayFunction (Built-in Mathematica Symbol)

$DisplayFunction gives the default setting for the option DisplayFunction in graphics functions.

$Display (Built-in Mathematica Symbol)

$Display gives a list of files and pipes to be used with the default $DisplayFunction.

$DistributedContexts (Built-in Mathematica Symbol)

$DistributedContexts is the default value of the DistributedContexts option of functions such as ParallelTable and ParallelMap.

$DynamicEvaluation (Built-in Mathematica Symbol)

$DynamicEvaluation is a symbol whose value is True if it is evaluated as part of the evaluation of a Dynamic.

$Echo (Built-in Mathematica Symbol)

$Echo gives a list of files and pipes to which all input is echoed.

$Epilog (Built-in Mathematica Symbol)

$Epilog is a symbol whose value, if any, is evaluated when a dialog or a Mathematica session is terminated.

$ExportFormats (Built-in Mathematica Symbol)

$ExportFormats gives a list of export formats currently supported in your Mathematica system.

$Failed (Built-in Mathematica Symbol)

$Failed is a special symbol returned by certain functions when they cannot do what they were asked to do.

$FrontEnd (Built-in Mathematica Symbol)

$FrontEnd is a global variable that specifies to what front end object, if any, the kernel is currently connected.

$FrontEndSession (Built-in Mathematica Symbol)

$FrontEndSession is a global symbol that represents the current session of the front end from which the kernel is being run.