A "minor" is like a "major" in college, but it takes fewer classes to complete. It usually requires that you take about 5-6 classes in one subject.

You can use the words "major in" and "minor in" as verbs:

I majored in Art History.

I considered minoring in French, but I would have had to stay an extra semester to finish it up.

Because a college minor is not as important as a major, it's not as common to say that you "are" a (something) minor or that your minor "is" something. People usually use the verb form instead.