I have a site where people post code snippets containing code of various types such as PHP, jQuery, CSS, HTML5, node.js, Android, iOS, etc. Currently I'm using the term "platform" to designate which of these disciplines the user can post. I know this term isn't accurate because CSS isn't a platform, it's a markup language and jQuery isn't a platform, it's a library. So in terms of UX and readability what term should I use? We already have tags, but these are not restricted to only programming languages, platforms, libraries or frameworks.
So the question is when posting a code snippet and I've got a dropdown containing PHP, jQuery, iOS, CSS to generally describe the snippet, what should the label be for the dropdown?

