n.1. Meteorology a. Any form of water, such as rain, snow, sleet, or hail, that falls to the earth's surface.
b. The quantity of such water falling in a specific area within a specific period.
2. A hastening or acceleration, especially one that is sudden or unexpected: He is responsible for the precipitation of his own demise.
3. Abrupt or impulsive haste.
4. A headlong fall or rush.
5. Chemistry The process of separating a substance from a solution as a solid.