Where does “graba” come from?

graba (Bikol Central) comes from Spanish grava, from Catalan grava, 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.

Ancestry of “graba”, step by step

Step	Language	Word	Meaning
1	Spanish	grava	gravel
2	Catalan	grava	gravel
3	Old French	gravé	gravel
4	Medieval Latin	grava	—
5	Gaulish	grawa	—
6	Proto-Celtic	grāwā	gravel, pebbles
7	Proto-Indo-European	gʰroh₁weh₂	—
8	Proto-Indo-European	gʰreh₁w-	to grind

Every word from Proto-Indo-European gʰreh₁w- →Every word from Proto-Indo-European gʰroh₁weh₂ →Every word from Proto-Celtic grāwā →