còi

• (Hà Nội) IPA^(key): [kɔj˨˩]
• (Huế) IPA^(key): [kɔj˦˩]
• (Saigon) IPA^(key): [kɔj˨˩]

From Proto-Vietic *t-kɔːj (“horn”). Cognate with Thavung təkɔːj¹ ("cow and buffalo horn"), Proto-Katuic *tŋkɔɔj (whence Pacoh tancoi (“horn, antler”)), Khmer កុយ (koy, “rhinoceros horn”). The original meaning was probably "horn of a herbivore", while Proto-Vietic *k-rəŋ (> sừng) was just "horn" in general.

The Viet-Muong languages no longer retain the meaning "horn of a herbivore" preserved in the other Vietic languages (like Thavung), Katuic and Khmer, but only "instrumental horn" (with the same semantic development as in English).

(classifier cái) còi • (𩲡, 𧥇)

1. a whistle (device used to make a whistling sound)
2. a horn (loud alarm, especially on a motor vehicle)
3. a siren (device for making a sound alarm)

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

còi • (孤, 𩲡)

1. (colloquial) skinny; bony

   Synonyms: gầy, ốm, ròm, tóm