Precipitation is a form of water from the atmosphere. It is a term in meteorology, and includes rain, snow, sleet, dew, frost, and hail. These form from atmospheric water vapor, and fall under gravity.
If liquid, precipitation can be measured using a rain gauge. The most common form of solid precipitation is snow. Snow is made when temperatures are so cold that water vapor changes directly to solid crystals. Frozen rain is hail or sleet.