Specifically refers to the source code from which applications may be compiled or the process of said compilation. Do not use to request a source of information or to determine the source from which Bitcoins originate, etc.
and the tag code that is only used in one place. To me it seems obvious that "source" and "code" are synonyms and should be renamed "source-code" to make it clearer. I'm not so sure about the other ones though. There is a merge request for "code" -> "development" that I'm not sure is right. Any suggestions of a description for the "development" tag?
Also, have a look at this older question and give your input there: Is there a way to resolve the ‘client’ and ‘developement’ tags ambiguities?