DocumentationMathematicaThe Mathematica BookMathematica Reference GuideSome General Notations and Conventions
Some built-in functions can take options. Each option has a name, represented as a symbol, or in some cases a string. Options are set by giving rules of the form name->value or name:>value. Such rules must appear after all the other arguments in a function. Rules for different options can be given in any order. If you do not explicitly give a rule for a particular option, a default setting for that option is used.
Operations on options.