To submerge means to go under the surface of water or another liquid, or to push something beneath the surface. When a submarine submerges, it sinks below the ocean's surface to travel hidden underwater. When you submerge your head in a swimming pool, you dip completely beneath the water.

You might submerge vegetables in boiling water to cook them, or submerge dirty dishes in soapy water before washing them. Divers submerge themselves to explore coral reefs. Some animals, like hippos and crocodiles, spend much of their time submerged with only their eyes and nostrils above the water.

Things can also become submerged accidentally. A town built in a valley might become submerged when a dam creates a reservoir, leaving buildings hidden underwater. After a heavy rainstorm, low-lying streets can become temporarily submerged in floodwater.

The word occasionally describes being overwhelmed or buried under something non-liquid, like when a student feels submerged under a pile of homework. But usually, submerge involves actual water or liquid covering something completely. The opposite is emerge, which means to rise up or come out from being underwater.