Where does “pennrudh” come from?

pennrudh (Cornish) comes from Cornish rudh, from Middle Cornish ruth,ruyth, from Old Cornish rud, from Proto-Brythonic rrʉð, from Proto-Celtic roudos, from Proto-Indo-European h₁rewdʰ- — red.

pennrudh (Cornish): bulrush, cattail, reedmace genus Typha

Definitions

  1. bulrush, cattail, reedmace genus Typha

Ancestry of “pennrudh”, step by step

pennrudh traces back through two separate lines of ancestry.

via Cornish rudh

StepLanguageWordMeaning
1Cornishrudhred
2Middle Cornishruth,ruyth—
3Old Cornishrud—
4Proto-Brythonicrrʉðred
5Proto-Celticroudosred
6Proto-Indo-Europeanh₁rewdʰ-red

via Cornish penn

StepLanguageWordMeaning
1Cornishpennhead; top; end
2Middle Cornishpen—
3Old Cornishpenhead
4Proto-Brythonicpennhead
5Proto-Celtickʷennomhead
Every word from Proto-Indo-European h₁rewdʰ- →Every word from Proto-Celtic roudos →Every word from Proto-Brythonic rrʉð →