The story
- Proto-Indo-European*bʰel-
- Proto-Indo-European*bʰleh₁-
- Proto-Indo-European*bʰleh₁wos
- Proto-Germanic*blēwaz
- Proto-West Germanic*blā
- Late Latinblāvus
- Anglo-Normanble
- Middle Englishblew
- Englishblue
- Proto-Indo-European*h₃ed-
- Proto-Indo-European*h₃dónts
- Proto-Germanic*tanþs
- Proto-West Germanic*tanþ
- Old Englishtōþ
- Middle Englishtoth
- Englishtooth
- Old NorseBlátǫnn
- English todayBluetooth
From blue + tooth. Calque of Old Norse Blátǫnn (compare modern Danish Blåtand). The networking standard is named after the king, since the technology unites computers and mobile devices similarly to the way he united the Danish tribes.
Etymology from Wiktionary, CC BY-SA 4.0.