The story
- Proto-Indo-European*bʰer-der.?
- Proto-Germanic*braidaz
- Proto-West Germanic*braid
- Old Englishbrād
- Middle Englishbrod
- Englishbroad
- Proto-Germanic*kas-
- Proto-Germanic*kastōną
- Old Norsekasta
- Middle Englishcasten
- Englishcast
- Englishbroadcast
- English today-cast
Back-formation from broadcast.
Etymology from Wiktionary, CC BY-SA 4.0.