The story
- Proto-Germanic · inherited from*brigdilaz“strap, rein”
- Proto-West Germanic · inherited from*brigdil
- Old English · inherited frombrīdel
- Middle English · inherited frombridel
- English todaybridle
From Middle English bridel, from Old English brīdel, from Proto-West Germanic *brigdil, from Proto-Germanic *brigdilaz (“strap, rein”), equivalent to braid + -le.
Etymology from Wiktionary, CC BY-SA 4.0.