Precipitate Definition: to form an insoluble compound either by reacting two salts or by changing the temperature to affect the solubility of the compound.Also the name given to the solid that is formed as a result of a precipitation reaction.Example: Mixing silver nitrate and sodium chloride in water will cause silver chloride to precipitate out of solution as a solid.Return to the Chemistry Glossary Index.recipitate Definition: to form an insoluble compound either by reacting two salts or by changing the temperature to affect the solubility of the compound.