PageBreakAbove is an option for Cell which specifies whether a page break should be made immediately above the cell if the notebook that contains the cell is printed.
PageBreakBelow is an option for Cell which specifies whether a page break should be made immediately below the cell if the notebook that contains the cell is printed.
Stub
(Built-in Mathematica Symbol) Stub is an attribute which specifies that if a symbol is ever used, Needs should automatically be called on the context of the symbol.
SyntaxLength["string"] finds the number of characters starting at the beginning of a string that correspond to syntactically correct input for a single Mathematica expression.
UsingFrontEnd[expr] evaluates expr, making use of a front end if necessary.
$InitialDirectory gives the initial directory when the current Mathematica session was started.
$MachineAddresses gives a list of strings specifying the current IP addresses associated with the computer on which Mathematica is being run.
$MachineDomains is a list of strings giving the names of the current network domains associated with the computer on which Mathematica is being run.
$MachineName is a string that gives the assigned name of the computer on which Mathematica is being run, if such a name is defined.
$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.