Where does “บาตร” come from?

บาตร (Thai) comes from Sanskrit पात्र, from Proto-Indo-European peh₃- — to drink.

บาตร (Thai): priest's alms bowl; pot

Definitions

Step	Language	Word	Meaning
1	Sanskrit	पात्र	a drinking vessel, goblet, bowl, cup, dish, pot,...
2	Proto-Indo-European	peh₃-	to drink

บาตร — Etymology, Origin & Word History | Etymology Explorer