Injection \In*jec"tion\, n. [L. injectio : cf.F. injection.]

1. The act of injecting or throwing in; -- applied particularly to the forcible throwing in of a liquid, or a["e]riform body, by means of a syringe, pump, etc.

2. That which is injected; especially, a liquid medicine thrown into a cavity of the body by a syringe or pipe; a clyster; an enema. --Mayne.

3. (Anat.)
   (a) The act or process of filling vessels, cavities, or tissues with a fluid or other substance.
   (b) A specimen prepared by injection.

4. (Steam Eng.)
   (a) The act of throwing cold water into a condenser to produce a vacuum.
   (b) The cold water thrown into a condenser.

Injection cock, or Injection valve (Steam Eng.), the cock or valve through which cold water is admitted into a condenser.

Injection condenser. See under Condenser.

Injection pipe, the pipe through which cold water is through into the condenser of a steam engine.

Source: Webster's Revised Unabridged Dictionary (1913)