"pre-requisite"?

why not just requisite?

I've seen 'pre-requisite' contrasted with 'co-requisite'. The former is a course you need to have taken before you can take another, while the oter can be taken at the same time. I suppose it is a little redundant.

A "requisite" is something that's required, whereas a "prerequesite" is something that's required beforehand.

That should be "prerequisite" of course.

If English 1 is a pre-requisite to English 2, then what is the requisite??

I guess requisite means the same thing but prerequisite indicates that something else is to follow.