Where does “k-ʔoːs” come from?

k-ʔoːs (Proto-Vietic) comes from Proto-Mon-Khmer pʔus — guava.

Ancestry of “k-ʔoːs”, step by step

Step	Language	Word	Meaning
1	Proto-Mon-Khmer	pʔus	guava

k-ʔoːs — Etymology, Origin & Word History | Etymology Explorer