It is mostly used as an adverb to show how two things are separated from one another. It can also serve as a preposition meaning “besides”. On the other hand, it can serve as an adjective in the context of “separate or isolated”.
Apart from the new Play station, what other device did Uncle Jackie buy for you? (As a preposition)
My Uncle and I learned how to grow fishes from our teacher’s farm, but we have our fish farms apart. (As an adverb)
The differences between Nowell books and Light Books are worlds apart. (As an adjective).
The two schools are 20 miles apart, meaning that you cannot go there.
Apart vs A part
Meaning of A part:
“A part” as the name implies is made up of two words; “A” and “part”. “A part” is a noun that means a portion of a whole. “A” from the word is an article while “part” means a piece of a whole.
I only took a part of the money to my mum.
A Part of what I told her was my relationship with David in the past.
Once you become a part of the superior team, I will get you a gift of encouragement.