EndOfString represents the end of a string for purposes of matching in StringExpression.
Environment["var"] gives the value of an operating system environment variable.
Equilibrium[x, y, ...] displays as x \[Equilibrium] y \[Equilibrium] ....
ErrorBox[boxes] is a low-level box construct that represents boxes that cannot be interpreted in input or output.
EvaluationElements is an option for NotebookEvaluate that determines which cells to evaluate.
ExcludePods is an option to WolframAlpha that specifies pod IDs to exclude from the results.
Exit
(Built-in Mathematica Symbol) Exit[] terminates a Mathematica kernel session.
ExponentPosition is an option for RadicalBox that specifies the placement of the index outside a radical sign.
ExportAutoReplacements is an option for cells that specifies which replacement rules Mathematica automatically applies when exporting text.
Expression is a symbol that represents an ordinary Mathematica expression in Read and related functions.