The story
- Proto-Indo-European*bʰrewh₁-
- Proto-Indo-European*bʰrenw-
- Proto-Indo-European*bʰrénuh₁e-?
- Proto-Germanic*brinnaną
- Proto-West Germanic*brinnan
- Old Englishbiernan
- Proto-Germanic*brinnaną
- Proto-Germanic*brannijaną
- Proto-West Germanic*brannijan
- Old Englishbærnan
- Old Norsebrenna
- Middle Englishbrennen
- Englishburn
- Proto-West Germanic*weud
- Old Englishwēod
- Middle Englishweed
- Englishweed
- English todayburnweed
From burn + weed, describing its rapid proliferation in areas which have recently been cleared by fire.
Etymology from Wiktionary, CC BY-SA 4.0.