This is the 9335th most frequent French word.
dam
A barrier built to hold back water.
Here, "barrage" refers specifically to a structure blocking the flow of water in a river, which is the literal meaning of 'dam' in French.
Le castor construit un barrage dans la rivière.
The beaver builds a dam in the river.
In this sentence, "barrage" denotes a man-made structure used for generating electricity by harnessing water flow.
La construction du barrage hydroélectrique prendra plusieurs années.
The construction of the hydroelectric dam will take several years.
While less common, 'barrage' can metaphorically refer to a blockade or defensive structure. Here, it has a military context of obstructing or controlling movement.