What’s the difference between OST, BGM, Soundtrack, and Theme Song?

Question

Up until now, I’ve been using OST & Soundtrack as the same thing because I’m an OST anime/movie/series/show collector. You can just check it here on YouTube in my playlists ([https://www.youtube.com/channel/UC_Z3eeDMIXMMBd6i4bFr3Gg/about](https://www.youtube.com/channel/UC_Z3eeDMIXMMBd6i4bFr3Gg/about)) ……. so it’s embarrassing enough to hear about “BGM” for the first time in an anime called Idolish7 & wonder what the heck is the difference between them all ……… *sigh*

If you could simply explain it & give me some examples, that’d be great thanks.

In: 1

Answer 1

Ost i think is the original sound track, bgm is background soundtrack?