Where does “Porthenys” come from?

Porthenys (Cornish) comes from Cornish porth, from Middle Cornish porth, from Old Cornish porth, from Proto-Brythonic porθ, from Latin porta, from Proto-Indo-European per-, from Proto-Indo-European pr̥tós — passed , crossed.

Ancestry of “Porthenys”, step by step

Porthenys traces back through two separate lines of ancestry.

via Cornish porth

StepLanguageWordMeaning
1Cornishporthharbor
2Middle Cornishporth
3Old Cornishporth
4Proto-Brythonicporθdoor, gate, gateway
5Latinportagate, especially of a city; entrance, passage,...
6Proto-Indo-Europeanper-before, in front; first; to go through
7Proto-Indo-Europeanpr̥tóspassed , crossed

via Cornish enys

StepLanguageWordMeaning
1Cornishenysisland
2Proto-Brythonicɨnɨsisland
3Proto-Celticenistīisland
4Proto-Indo-Europeanh₁eni-sth₂-ih₂
5Proto-Indo-Europeansteh₂-to stand
Every word from Proto-Indo-European pr̥tósEvery word from Proto-Indo-European per-Every word from Latin porta