Block
(Built-in Mathematica Symbol) Block[{x, y, ...}, expr] specifies that expr is to be evaluated with local values for the symbols x, y, .... Block[{x = x_0, ...}, expr] defines initial local values for x, ...
ButtonData is an option for the low-level function ButtonBox that specifies the second argument to give to the ButtonFunction for the button when the button is active and is ...
CellOpen is an option for Cell that specifies whether the contents of a cell should be explicitly displayed.
DedekindEta[\[Tau]] gives the Dedekind eta modular elliptic function \[Eta](\[Tau]).
DefaultElement is an option for Grid and related constructs which specifies what to insert when a new element is interactively created.
EllipticNomeQ[m] gives the nome q corresponding to the parameter m in an elliptic function.
EvaluationElements is an option for NotebookEvaluate that determines which cells to evaluate.
Expression is a symbol that represents an ordinary Mathematica expression in Read and related functions.
InverseHaversine[z] gives the inverse haversine function hav -1 (z).
Log2
(Built-in Mathematica Symbol) Log2[x] gives the base-2 logarithm of x.