SEDE: How many tags were created in one question?

SEDE: List of tags created in the given question

When I recently checked my sugested edit queue, it contained three different edits where the tag "solid-geometry" was added to a post. I didn't know this tag and the description does not really help - it claims to be about all 3D Euclidean space, but references a Wikipedia page that claims it's about 3D solids (and which has a lack of citation warning). What does it mean? Should the explanation of the tag (that isn't used that often) be improved?

(For reference, the two that I feel I rejected correctly are math.stackexchange.com/questions/128991/… and math.stackexchange.com/questions/73237/… which deal with 2D objects in 3D; the third one I should have approved.)