Where does “ไพศาล” come from?

ไพศาล (Thai) comes from Sanskrit विशाल, from Sanskrit वि-, from Proto-Indo-European wi — apart, asunder; away from, against.

ไพศาล (Thai): large

Definitions

Step	Language	Word	Meaning
1	Sanskrit	विशाल	spacious, extensive, broad, wide, large; great,...
2	Sanskrit	वि-	Prefix to verbs or nouns and other parts of...
3	Proto-Indo-European	wi	apart, asunder; away from, against

ไพศาล — Etymology, Origin & Word History | Etymology Explorer