Where does “rigosan” come from?

rigosan (Bikol Central) comes from Bikol Central -an, from Proto-Philippine *-an, from Proto-Malayo-Polynesian -an, from Proto-Austronesian -an — Verbal suffix marking locative focus; Nominal...

Ancestry of “rigosan”, step by step

Step	Language	Word	Meaning
1	Bikol Central	-an	a place where a large quantity of the thing meant...
2	Proto-Philippine	*-an	verbal suffix marking locative focus
3	Proto-Malayo-Polynesian	-an	Verbal suffix marking locative focus; Nominal...
4	Proto-Austronesian	-an	Verbal suffix marking locative focus; Nominal...

Every word from Proto-Austronesian -an →Every word from Bikol Central -an →Every word from Proto-Philippine *-an →