Where does “ซอด้วง” come from?

ซอด้วง (Thai) comes from Thai ด้วง, from Proto-Tai ɗuəŋᶜ — coconut grub.

ซอด้วง (Thai): saw duang, a Thai two-string vertical fiddle...

Definitions

Step	Language	Word	Meaning
1	Thai	ด้วง	beetle, weevil; caterpillar, pupa, grub, worm,...
2	Proto-Tai	ɗuəŋᶜ	coconut grub

ซอด้วง — Etymology, Origin & Word History | Etymology Explorer