The story
- Proto-Indo-European*upó
- Proto-Germanic*ub
- Proto-Germanic*upp
- Proto-West Germanic*upp
- Old Englishupp
- Middle Englishup
- Middle Englishupper
- English todayupper
Inherited from Middle English upper. By surface analysis, up + -er.
Etymology from Wiktionary, CC BY-SA 4.0.