Aceros is a genus of Asian hornbills (family Bucerotidae).

Bucerotiformes, Bucerotidae, Buceros: Latin bucerus horned like an ox (Greek boukeros: horned like an ox: bous ox; keros: horn).
Aceros: Greek akeros: hornless.

1/  Rufous-necked hornbill (Niệc cổ hung, Aceros nipalensis) 

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