JankoGroupJ2[] represents the sporadic simple Janko group J_2.
LibraryFunction[args] represents a function that has been loaded from a Wolfram Library.
LightingAngle is an option for ReliefPlot and related functions that specifies the angle from which simulated illumination is taken to come.
MaxStepSize is an option to functions like NDSolve that specifies the maximum size of a single step used in generating a result.
MessageDialog[expr] puts up a standard message dialog that displays expr together with an OK button.MessageDialog[expr, {lbl_1 :> act_1, lbl_2 :> act_2, ...}] includes ...
MultiedgeStyle is an option for GraphPlot and related functions that specifies how to draw multiple edges.
MultivariateHypergeometricDistribution[n, {m_1, m_2, ..., m_k}] represents a multivariate hypergeometric distribution with n draws without replacement from a collection ...
NumberSeparator is an option for NumberForm and related functions which gives the string to insert at breaks between digits.
OpenRead["file"] opens a file to read data from, and returns an InputStream object.
p : v is a pattern object that represents an expression of the form p, which, if omitted, should be replaced by v.