This is the 338th most frequent Vietnamese word.
sông
"River."
Here, 'sông' means 'river' and is used as a noun representing a geographical feature.
Sông Hồng chảy qua nhiều tỉnh thành.
The Red River flows through many provinces.
In this sentence, 'sông' again refers to a river, used as the habitat in the context.
Có nhiều loài cá sống trong sông.
There are many species of fish living in the river.
Here, 'sông' is used in a cultural context, suggesting historical or folklore relevance it holds.