Questions related to handling built-in symbols and functions, for example why they behave a certain (possibly unexpected) way.

Symbols are the basic named objects in Mathematica, and Mathematica comes with thousands of built-in symbols.

They may represent

  • functions (e.g. Plot, Exp);
  • constants (e.g. Pi, GoldenRatio, True);
  • (inert) names (option names like Method, AspectRatio; other names like $Failed);
  • function-like objects that do not evaluate to other expressions but derive their meaning from their Attributes (e.g. Hold) or how they are used by other parts of the system (e.g. RGBColor, Dynamic, C, K).

Some care should be exercised in using this tag, since nearly all questions will be about at least one built-in symbol. When the question is not about how to get a certain computation done but about how a certain symbol works, consider using this tag. A counterpart to this tag is the tag (q.v.), which should be used when the question is about the undocumented behavior of a symbol.

All of the system symbols may be listed with Names:

systemsymbols = Names["System`*"]; (* a very long list *)

Information about a symbol may be obtained with Information (?):

? Plot

There are also other contexts and packages built into Mathematica.