A pet peeve of mine:

Suppose you’re writing a story, and one of your characters is studying for a PhD in linguistics. You could call them a grad student or a PhD student, a linguistics student or even just a linguist. But one thing you absolutely shouldn’t call them is a linguistics major.

Graduate degrees, from the PhD to medical doctors to masters degrees, don’t have majors. Majors are a very specific concept, from a very specific system: one that only applies to undergraduate degrees, and even there is uncommon to unheard of in most of the world.

You can think of “major” as short for “major area of study”. In many universities in the US, bachelor’s degree students enter not as students of a particular topic, but as “undecided” students. They then have some amount of time to choose a major. Majors define some of your courses, but not all of them. You can also have “minors”, minor areas of study where you take a few courses from another department, and you typically have to take some number of general courses from other departments as well. Overall, the US system for bachelor’s students is quite flexible. The idea is that students can choose from a wide range of courses offered by different departments at a university, focusing on one department’s program but sampling from many. The major is your major focus, but not your only focus.

Basically no other degree works this way.

In Europe, bachelor’s degree students sign up as students of a specific department. By default, all of their courses will be from that department. If you have to learn more math, or writing skills, then normally your department will have its own math or writing course, focused on the needs of their degree. It can be possible to take courses from other departments, but it’s not common and it’s often not easy, sometimes requiring special permission. You’re supposed to have done your general education as a high school student, and be ready to focus on a particular area.

Graduate degrees in the US also don’t work this way. A student in medical school or law school isn’t a medicine major or a law major, they’re a med student or a law student. They typically don’t take courses from the rest of the university at that point, just from the med school or the law school. A student studying for an MBA (Master’s in Business Administration) is similarly a business student, not the business major they might have been during their bachelor’s studies. And a student studying for a PhD is a PhD student, a student of a specific department. They might still have the option of taking classes outside of that department (for example, I took classes in science communication). But these are special exceptions. A linguistics PhD student will take almost all of their classes from the linguistics department, a physics PhD student will take almost all of their classes from the physics department. They don’t have majors.

So the next time you write a story with people with advanced degrees, keep this in mind. Majors are a thing for US bachelor’s degrees, and a few similar systems. Anything else, don’t call it a major!