StartScheduledTask[obj] starts the task represented by obj.
PolarTicks is an option for sector charts and polar plots that specifies tick marks for polar axes.
ColorSpace is an option for Image and related functions that specifies the color space to which color values refer.
DefaultDuration is an option to Animate and related functions that specifies the default total duration of the animation in seconds.
RefreshRate is an option to Animate and related functions which specifies the refresh rate for frames in animations.
SpellingCorrection is an option for StringMatchQ, Names, and related functions that specifies whether strings should be considered to match even when a small fraction of the ...
TextPacket[string] is a MathLink packet containing string, the text output from Mathematica as produced by functions such as Print.
$Failed
(Built-in Mathematica Symbol) $Failed is a special symbol returned by certain functions when they cannot do what they were asked to do.
$PerformanceGoal gives the default setting for the option PerformanceGoal for graphics and other algorithmic functions.