Crested kingfisher 
(Bói cá mào or Bói cá lớn, Megaceryle lugubris) 

The crested kingfisher (Megaceryle lugubris) is a very large kingfisher that is native to parts of southern Asia.
The bird can be seen from northeast Afghanistan to central Vietnam and Japan.

Alcedo, Alcedinidae: Latin word for kingfisher. 
Megaceryle is from the Ancient Greek megas, "great", and the existing genus Ceryle which is from Greek kerulos bird mentioned by Aristotle,.. but not further identified but probably mythical and associated with the halcyon, a kingfisher.
The specific name lugubris is the Latin word for "mournful".