Where does “Dylan” come from?

Dylan (Welsh) comes from Welsh dy-, from Proto-Celtic dus-, from Proto-Indo-European dus-, from Proto-Indo-European dēwǝ- — to fail, be behind, be lacking.

Ancestry of “Dylan”, step by step

StepLanguageWordMeaning
1Welshdy-bad; to, together
2Proto-Celticdus-bad
3Proto-Indo-Europeandus-bad
4Proto-Indo-Europeandēwǝ-to fail, be behind, be lacking
Every word from Proto-Indo-European dēwǝ- →Every word from Proto-Indo-European dus- →Every word from Welsh dy- →