Learn Turkish: Toplantıda not aldım. - I took notes in the meeting.

In Turkish, general or indefinite objects are usually kept singular. Because you are talking about the general activity of taking notes rather than specific individual notes, you just use the singular not.

Why isn't there an accusative case suffix on not (making it notu)?

The accusative case is only used for specific, definite objects (like "the notes" or "my notes"). Since these are general, indefinite notes, the word stays plain and sits directly in front of the verb.

I learned that almak means "to buy". Can it also mean "to take"?

Yes! Almak is a very versatile verb. It can mean "to buy," "to receive," or "to take." Fortunately, just like in English, Turkish uses this verb for the exact phrase "to take notes" (not almak).

What is the base word of toplantıda?

The base noun is toplantı, which means "meeting." The -da at the end is the locative case suffix, meaning "in" or "at," so toplantıda means "in the meeting."