Parmandur
Book-Friend
1e AD&D PHB:
It was initially contemplated to term character power as rank, spell complexity was to be termed power, and monster strength was to be termed as order. Thus, instead of a 9th level character encountering a 7th level monster on the 8th dungeon level and attacking it with a 4th level spell, the terminology would have been: A 9th rank character encountered a 7th order monster on the 8th (dungeon) level and attacked it with a 4th power spell. However, because of existing usage, level is retained throughout with all four meanings, and it is not as confusing as it may now seem.
Really kind of wish they bit the bullet at that point. Too late now, unfortunately.