injection: Meaning and Definition of

in•jec•tion

1. the act of injecting.
2. something that is injected.
3. a liquid injected into the body, esp. for medicinal purposes, as a hypodermic or an enema.
4. state of being hyperemic or bloodshot.
5. a one-to-one function.
6. Also calledthe process of putting a spacecraft into orbit or some other desired trajectory.