The form of water that falls to the earth in form of rain is called precipitation.
Precipitation is any type of water that forms in the earth's atmosphere and then drops onto the surface of the earth. Water vapor ( droplets of water suspended in the air) build up in the earth's atmosphere and condenses to form clouds. Once the clouds get too full of water, they precipitate into liquid i.e. rain which falls to the earth.
Precipitation is part of the water cycle and it falls to the ground as rain or snow. It eventually evaporates and rises back into the atmosphere as a gas.