Where does “deróil” come from?

deróil (Old Irish) comes from Old Irish ro-, from Proto-Celtic ɸro-, from Proto-Indo-European per-, from Proto-Indo-European pr̥tós — passed , crossed.

Ancestry of “deróil”, step by step

StepLanguageWordMeaning
1Old Irishro-indicates a perfective aspect; indicates...
2Proto-Celticɸro-before, in front of; in addition; to completion
3Proto-Indo-Europeanper-before, in front; first; to go through
4Proto-Indo-Europeanpr̥tóspassed , crossed
Every word from Proto-Indo-European pr̥tós →Every word from Proto-Indo-European per- →Every word from Old Irish ro- →