Where does “grav” come from?

grav (Romanian) comes from French gravé, from Middle French grave, from Old French gravé, from Medieval Latin grava, from Gaulish grawa, from Proto-Celtic grāwā, from Proto-Indo-European gʰroh₁weh₂, from Proto-Indo-European gʰreh₁w- — to grind.

grav (Romanian): grave, serious; critical, important, weighty;...