Toks said:
From wikipedia :
[...]
tl;dr: Doesn't necessarily need to be paper to count as sheet music.
I recommend using Danbooru's specific disambiguation between the two rather than the Wikipedia entry. I think it's useful to have two distinct tags for music on paper and music as part of the background or scenery.
Aside: In addition to staff (music), there's also the tag musical staff. One should probably be aliased to the other.
Staff (music) is the older tag with the greater number of posts (127 v. 14), so that one will probably win out.
On the other hand, we have musical note and not note (music), so there's greater consistency in going the other way. Also it flows better if you're using autocomplete to find tags you aren't familiar with, and you're not musical enough to automatically think of the staff as the first word to search on.