Where does “chữ Nôm” come from?

chữ Nôm (Vietnamese) comes from Vietnamese Nôm, from Old Portuguese non, from Latin nōn, from Old Latin noenum, from Proto-Indo-European óynos — one; single.

chữ Nôm (Vietnamese): a historical writing system based on Chinese...

Definitions

a historical writing system based on Chinese...

Ancestry of “chữ Nôm”, step by step

chữ Nôm traces back through two separate lines of ancestry.

via Vietnamese Nôm

Step	Language	Word	Meaning
1	Vietnamese	Nôm	written in Vietnamese using chữ Nôm
2	Old Portuguese	non	no, not
3	Latin	nōn	not
4	Old Latin	noenum	—
5	Proto-Indo-European	óynos	one; single

via Vietnamese chữ

Step	Language	Word	Meaning
1	Vietnamese	chữ	alphabet, writing system, script; letter,...
2	Proto-Vietic	cuːʔ	grandchild; father's younger brother
3	Proto-Mon-Khmer	cuuʔ	grandchild

Words derived from “chữ Nôm”

チュノム

Every word from Proto-Indo-European óynos →Every word from Old Latin noenum →Every word from Latin nōn →