sông Cửu Long

Etymology
+, literally “River of the Nine Dragons”, referring to the nine main distributaries of the Mekong in its lower reaches before it enters the sea.

An alternative theory holds that Cửu Long is essentially a disyllabified, Sino-Vietnamese, whence Modern Vietnamese. Although this practice is widely attested (compare vs.,  vs. ,  vs. ), the geographical remoteness from the Vietnamese heartland (Northern and North Central Vietnam) and the rather recent settlement history of Vietnamese speakers in the region may cast some doubt on the theory.