Product SiteDocumentation Site Symbols

As stated in the section about variables, a symbol is simply something which represents something else. When used in the context of a SynthDef, a symbol is a string of characters that refers to a SynthDef that we've already sent to the server. What wasn't mentioned in the section about variables is that, in addition to the symbols that can be used as variable names, the SuperCollider language provides a distinct data-type (like numbers or strings) for symbols. Many programming languages don't provide a "symbol" data-type, so many programmers do not use them extensively, but they are very handy for situations like this. As local variable names are symbols representing data stored by the interpreter, here we are using the symbol data-type to refer to data stored on the server.
Symbols are a better way to name SynthDef's than strings. Not only do symbols take up less memory, they aren't actually the interpreter doesn't actually think of them as Objects, and neither should you. Symbols are universally unique; only one instance of a symbol with the same characters can exist. On the other hand, an infinite number of strings with the same characters can exist. When we use a symbol, we are defining it universally. When we use a string, the server pretends that all strings with the same characters are the same philosophical object, even though they aren't. This isn't a technical problem, but it can be difficult to think about, and is cognitively dissonant.
If all this seems a little abstract and ontological, that's because it is. Symbols: the Easy Way
Symbols are things that you should use to identify a SynthDef sent to the server.