1 To initiate an action or enable a data path.
2 To choose one of several possible control paths at a particular point in a program. The selection operation is usually made by a case statement, though if there are only two alternatives an if then else statement can be used.
3 To mark out a section of a document before performing an operation on it, such as copy, move, or cut, or before changing its attributes, such as font, color, margins, or line spacing. The selection process can be done using the keyboard or by dragging the cursor with a pointing device such as a mouse. The marked text is known as the selection.
4 To indicate an item in a menu, menu bar, button bar, etc., with the selection cursor before initiating an action.