Where does “Pennderves” come from?

Pennderves (Cornish) comes from Cornish penn, from Middle Cornish pen, from Old Cornish pen, from Proto-Brythonic penn, from Proto-Celtic kʷennom — head.

Ancestry of “Pennderves”, step by step

Step	Language	Word	Meaning
1	Cornish	penn	head; top; end
2	Middle Cornish	pen	—
3	Old Cornish	pen	head
4	Proto-Brythonic	penn	head
5	Proto-Celtic	kʷennom	head

Every word from Proto-Celtic kʷennom →Every word from Proto-Brythonic penn →Every word from Old Cornish pen →