1. The act of making something happen suddenly and quickly: The thoughtless hiker was responsible for the precipitation of rocks abruptly falling down the hillside.
2. A casting down or falling headlong: Little Tommy tumbled down from the top step of the long staircase and this precipitation terrified and alarmed his parents greatly!
3. A hastening or hurrying in movement, procedure, or action: Jack's friends were convinced that he was responsible for the precipitation of his death because of his addiction to alcoholic beverages.
4. Sudden haste: The precipitation Janet showed by leaving so abruptly and without saying goodbye took all of her friends by complete surprise.
5. Unwise or rash rapidity: The burglar's precipitation from the house was completely foolish because he was immediately caught right outside before he could flee!
6. In meteorology, falling products of condensation in the atmosphere, such as snow or hail: When the weather forecast predicted a high level of precipitation, people had to expect a lot of rain.
7. The amount of snow, hail, etc., that has fallen at a given place within a given period, usually expressed in inches or centimeters of water: Ivy went outside to check the device that showed the precipitation of rain the night before.
8. In chemistry and physics, the separation of a solid substance from a solution: In precipitation, crystals assume a dense form when a point of total saturation has been attained.
9. Etymology: "sudden haste", from Middle French precipitation (15th century); directly from Latin praecipitationem, praecipitatio, "act" or "fact of falling headlong, haste, steep place"; from praecipitare, "to throw headlong, to fall, to be hasty"; from praeceps "headlong, steep"; which was a compound formed from the prefix prae-, "in front" + capit, caput, "head".

A procedure using an electric field to enhance the separation of hydrocarbon reagent dispersions: "Electric precipitation makes the separation of hydrocarbon dispersions more efficient because such a process of scatterings or divisions are too fine to accomplish efficiently by any other method."

The removal of dust, smoke, or other finely divided particles from the air by charging the particles with an electric field so they are attracted to oppositely charged collector electrodes and collected by those polarized electrodes.

Precipitation which results from the lifting of moist air over a topographic barrier; such as, a mountain range: "The orographic precipitation may take place at some distance upwind or a short distance downwind, as well as on the barrier itself."