Where does “Trefaldwyn” come from?

Trefaldwyn (Welsh) comes from Welsh Aldwyn, from Old English Ealdwine, from Old English eald, from Old English feld, from Proto-West Germanic felþu, from Proto-Germanic felþuz, from Proto-Indo-European pelh₂-, from Proto-Indo-European pel- — to cover, to wrap; skin, hide, cloth; to fold.

Ancestry of “Trefaldwyn”, step by step

Trefaldwyn traces back through two separate lines of ancestry.

via Welsh Aldwyn

StepLanguageWordMeaning
1WelshAldwyn
2Old EnglishEaldwine
3Old Englishealdold; ancient; original
4Old Englishfeldfield
5Proto-West Germanicfelþufield
6Proto-Germanicfelþuzfield, plain
7Proto-Indo-Europeanpelh₂-to approach
8Proto-Indo-Europeanpel-to cover, to wrap; skin, hide, cloth; to fold

via Welsh tref

StepLanguageWordMeaning
1Welshtreftown; home
2Middle Welshtreftown
3Proto-Brythonictreβtown, settlement
4Proto-Celtictrebādwelling
5Proto-Indo-Europeantreb-settlement, dwelling; to build, dwell
Every word from Proto-Indo-European pel-