Is there an open / established categorization / list of terms / concepts and synonyms for mathematics?

Question

I am currently thinking about how to bundle some of the efforts of students to get / create good educational material. One idea of this little project (wiki-ed - still in the very early phase) is to add machine-readable meta information to content which states what the material (e.g. lecture notes) are teaching and which skills they require. Having a lot of educational material with this kind of meta-data should allow students to search for what they are interested in and find the minimum material they need to know to understand it.

However, stating what is required and what is taught is difficult, as one might have different names. For example:

1. natural numbers
2. Natural numbers
3. Natural Numbers
4. set of natural numbers
5. N
6. $\mathbb{N}$

So there is need for a way to look for one way to describe it. I think I have read something like this for American / British math students.

Is there such a freely available list which defines such concepts and gives them names?

Answer 1

What I was looking for is Mathematics Subject Classification:

The Mathematics Subject Classification (MSC) is an alphanumerical classification scheme collaboratively produced by staff of, and based on the coverage of, the two major mathematical reviewing databases, Mathematical Reviews and Zentralblatt MATH. It is used by many mathematics journals, which ask authors of research papers and expository articles to list subject codes from the Mathematics Subject Classification in their papers. The current version is MSC2010.

One can download it here: http://www.ams.org/msc/msc2010.html

It only defines different sub-fields of mathematics, but not concepts as far as I can see. However, this was what I was looking for when I wrote "American / British math students".

So if you know a similar categorization for concepts / terminology, I would still be happy to read about it.