SpanAdjustments is an option for selections that specifies the height and width of spanning characters.
SpanSymmetric is an option for selections that specifies whether vertically expandable characters are symmetric about the axis of the selection.
TooltipDelay is an option for objects such as Tooltip that specifies how long to delay after the mouse is over the object before displaying the tooltip.
WindowToolbars is a notebook option that specifies the toolbars to include at the top of the window used to display the notebook on the screen.
$Echo
(Built-in Mathematica Symbol) $Echo gives a list of files and pipes to which all input is echoed.
$GeoLocation is a settable global variable that specifies the default geodetic location to use.
$MachineDomains is a list of strings giving the names of the current network domains associated with the computer on which Mathematica is being run.
$NewMessage is a global variable which, if set, is applied to the symbol name and tag of messages that are requested but have not yet been defined.
Cells as Mathematica Expressions Notebooks as Mathematica Expressions Manipulating Notebooks from the Kernel
Functions in Mathematica are carefully set up so that you normally do not have to know how they work inside. But particularly for numerical functions that use iterative ...