Where does “Llewellyn” come from?

Llewellyn is an English adoption of Welsh Llywelyn, from Proto-Brythonic Lluɣβelen, derived from Proto-Celtic Lugus.

Ancestry of “Llewellyn”, step by step

StepLanguageWordMeaning
1WelshLlywelyn—
2Proto-BrythonicLluɣβelen—
3Proto-CelticLugusthe god {{w|Lugus}}
Every word from Proto-Celtic Lugus →Every word from Proto-Brythonic Lluɣβelen →Every word from Welsh Llywelyn →