I've read in a ton of places a lot of different definitions for a bunch of musical terms, so I'm trying to understand just exactly what they all mean. I don't quite understand what meter is, but from what I've read it is a group of 2 or 3 notes. Places have stated that 4/4 is a meter, but I thought that was a time signature. Compound meter is also confusing. I've read that's it's something that can be divided by 3 like 9/8, and I've read elsewhere that it's a combination of 2 and 3 like 5/8. So in addition to not knowing what compound meter actually is, I'm also confused because some places seem to use meter and time signature interchangeably. I also don't understand polyrhythms and polymeters. There is a drum beat that has a foot rhythm of three beats, that goes 4 & 1 with straight eights. Then the right hand plays three straight eighth notes that go 1 & 2. My drum teacher said that it's polyrhythmic, but my theory teacher said polyrhythmic is something like triplets on top of straight eighth notes. Then there is a drum beat Danney Carey plays in a song I'm not sure of, playing hihat sixteenths with an open hit every third sixteenth note, over a kick and snare part in 4/4. So the right hand is 12/16 and the kick and snare are 4/4, and it lines up after four 4/4 bars. Some say this is polyrhythmic, some say it's polymetric. Also, what would it be called if there was a song with one instrument playing 5/4 while the other is in 4/4? I'm confused about what these things actually are because I've seen so many definitions.