Where does “cài áo” come from?

cài áo (Vietnamese) comes from Vietnamese áo, from Proto-Vietic ʔaːwʔ, from Proto-Mon-Khmer ʔaawʔ — upper garment.

cài áo (Vietnamese): a brooch; ornamental clothing fastener

Definitions

  1. a brooch; ornamental clothing fastener

Ancestry of “cài áo”, step by step

cài áo traces back through two separate lines of ancestry.

via Vietnamese áo

StepLanguageWordMeaning
1Vietnameseáoa top; an outfit
2Proto-Vieticʔaːwʔ—
3Proto-Mon-Khmerʔaawʔupper garment

via Vietnamese cái

StepLanguageWordMeaning
1Vietnamesecáia thing; a whatsit; the solid bits of a broth;...
2Proto-Vietic-keːʔwoman, female
Every word from Proto-Mon-Khmer ʔaawʔ →Every word from Proto-Vietic ʔaːwʔ →Every word from Vietnamese áo →