I know what enumeration types are. Symbols are not directly an 'enumerated type', but can be used to implement them. Like symbols can be used for many other things. Thinking of symbols as elements of 'infinite enumerated type' is misleading or useless. In Common Lisp symbols are not just a name, but part of a namespace (package), have a value, a function, a property list, etc.. They can only be kind of enumerated if they are part of a package. Symbols can also be not interned in a package, then you can't enumerate them.