Asian openbill 
or Asian openbill stork 
(Cò nhạn, Cò ốc, Anastomus oscitans)

The Asian openbill or Asian openbill stork (Anastomus oscitans) is a large wading bird in the stork family Ciconiidae.

Ciconiiformes, Ciconiidae: from Latin ciconia for stork.
Anastomus: from the Ancient Greek anastomoō meaning "to furnish with a mouth" or "with mouth wide-opened".
The specific epithet oscitans is the Latin word for "yawning", oscitare to yawn, Bec-ouvert.