1. (n.) The act of injecting or throwing in; -- applied particularly to the forcible throwing in of a liquid, or aeriform body, by means of a syringe, pump, etc.
2. (n.) That which is injected; especially, a liquid medicine thrown into a cavity of the body by a syringe or pipe; a clyster; an enema.
3. (n.) The act or process of filling vessels, cavities, or tissues with a fluid or other substance.
4. (n.) A specimen prepared by injection.
5. (n.) The act of throwing cold water into a condenser to produce a vacuum.