DefaultElement is an option for Grid and related constructs which specifies what to insert when a new element is interactively created.

DefaultFontProperties is a global option that specifies various properties of a font family, such as its character encoding and whether it is monospaced.

DefaultNewInlineCellStyle is an option for cells that specifies the default style to use for new inline cells created in the notebook.

EndOfString represents the end of a string for purposes of matching in StringExpression.

ExternalDataCharacterEncoding is a global option that specifies the character encoding used in reading and writing plain text data outside of Mathematica.

FiniteAbelianGroupCount[n] gives the number of finite Abelian groups of order n.

<< name reads in a file, evaluating each expression in it, and returning the last one.

InputNamePacket[string] is a MathLink packet that contains in string the name to be assigned to the next input.

InputStringPacket[] is a MathLink packet that requests input in string form.

InverseHaversine[z] gives the inverse haversine function hav -1 (z).