Welcome Screen opens the Welcome Screen, which appears by default each time you start Mathematica.

Wolfram Website opens the main Wolfram Research website in a web brower.

Wrap at Paper Width wraps lines at the width of the paper currently specified by the print settings.

Wrap at Window Width wraps lines at the width of the window containing the text.

ActionMenu[name, {lbl_1 :> act_1, lbl_2 :> act_2, ...}] represents an action menu with label name and with items labeled lbl_i that evaluates the expression act_i if the ...

Arrow[{pt_1, pt_2}] is a graphics primitive that represents an arrow from pt_1 to pt_2.Arrow[{pt_1, pt_2}, s] represents an arrow with its ends set back from pt_1 and pt_2 by ...

AutorunSequencing is an option for Manipulate that specifies how autorun should use the controls provided.

ButtonNotebook[] gives the notebook, if any, that contains the button which initiated the current evaluation.

CellPrint[expr] inserts expr as a complete cell in the current notebook just below the cell being evaluated. CellPrint[{expr_1, expr_2, ...}] inserts a sequence of cells.

ColorRules is an option for ArrayPlot which specifies how colors of cells should be determined from values.