The story
- Proto-Indo-European*bʰeg-der.?
- Proto-Germanic*baką
- Proto-West Germanic*bak
- Old Englishbæc
- Middle Englishbak
- Englishback
- Proto-Indo-European*Hrew-?
- Proto-Indo-European*(H)rewH-
- Proto-Germanic*rūmą
- Proto-West Germanic*rūm
- Old Englishrūm
- Middle Englishroum
- Englishroom
- English todaybackroom
Etymology from Wiktionary, CC BY-SA 4.0.