Where does “ហាង” come from?

ហាង (Khmer) comes from Thai หาง, from Proto-Tai trwɤːŋᴬ — tail.

ហាង (Khmer): tail; shop, store

Definitions

Step	Language	Word	Meaning
1	Thai	หาง	tail; end of an object
2	Proto-Tai	trwɤːŋᴬ	tail

ហាង — Etymology, Origin & Word History | Etymology Explorer