To "flatten" a note in music can mean moving it down a half step, like E to E flat, but it can also mean hitting a note in-between E and E flat.
Melisma can mean singing one syllable with various notes, as written out in the music--or it can mean more improvised style characteristic of Whitney Houston, etc..., in which the melisma is an ornamental feature rather than something written into the original song. In the first kind, the notes are more distinct; in the second kind, the singer is moving through glissando-like through various notes.
It seems like some musical terms are rather tricky to define. Those are the two that come to mind, though I'm sure there are others.
A book on the neuroscience of music talks about what emotions the music arouses. You can strap people with electrodes and actually see that. A book on the philosophy of music speculates about whether music triggers emotions in the first place.
So music can be approaches by a musicologist, from within the literature Western musical tradition. It can be approached by an Oliver Sacks from the neurological perspective; or by philosophers with a particular genealogy of thought about music, etc... There is not much crosswise moment among people interested in talking about music. A literary critic, like me, can read it all.