Architecture is a field of work and study that deals with designing buildings. An architect creates plans, called blueprints, which tell workers how to build a building.

You should notice that:

• an architect is a person. "Architect" is a job title that people have.
• Architecture is a field. It's something that architects study.

In American universities, students choose a "major", which is the main subject that they study. Students usually have to take a few classes in a variety of different subjects: science, math, English, social sciences, etc. But most of their classes are within their major. So if you're an Architecture major, you might have to take 10-15 classes (which equals 30-45 "hours" in the American university system) on different Architecture-related topics.

You can say that you "are" or "were" a certain major:

I was an English Literature major.

You can also say that your major "is" or "was" something:

What's your major?

Biochemistry.