There’s a little known protocol out there called the "dict" protocol which enables clients to connect to a dictionary server and query it for definitions. Servers can (and usually do) host multiple dictionaries, many of which are specialized. For instance, a single server might host the "freedict" standard dictionary, some translation dictionaries, a thesaurus, and maybe a dictionary specific to computer jargon (FOLDOC: The Free Online Dictionary of Computing).
I wrote an Apollo application called "Lookup" which is a versatile dictionary client. It lets you choose a server, choose a dictionary on a particular server, and interactively query it. I’ll release Lookup as soon as there is a public Apollo release, but in the meantime, I went ahead and checked the dict protocol library into the Adobe Labs source code repository. If you think you might have a need to look up words from ActionScript, check it out. It’s not well documented, but if you start with the Dict class, it’s pretty easy to figure out.