[lispm]

Lisp has symbols, because they were used in symbolic expressions (s-expressions) as named entities. In the programming language Lisp these symbols serve also as identifiers for functions, variables and other things. Thus a symbol originally had an internal structure made of an association list (a list of keys and values). That association list then had various entries, including a print name -> the thing to print when a symbol gets externalized. Since symbols can serve as function names, these symbols also had functions stored in their association list. Different function types could be stored under different keys.

Since Lisp symbols serve a central role as identifiers and structured objects, they are not like what Ruby uses. Lisp uses symbols also for named interned things, but that is only one purpose.

In Common Lisp symbols have a name, a value, a function, a package and a property list (a list of keys and their values). By default in a call like (mult 1 2 3), the global function will be retrieved from the symbol and the function will be called with the arguments. The property list sometimes will be used by an IDE to store information about the symbol: like where it was defined, what its definition is and similar.