This is the 578th most frequent Chinese word.
河
River.
In this sentence, '河' refers to a river, specifically as a natural watercourse.
这条河流经了三座城市。
This river flows through three cities.
Here, '河' is used to indicate the location by the riverbank.
河边的景色非常美丽。
The scenery by the river is very beautiful.
In this context, '河' indicates the river as a resource around which human activities are centered.