transitive verb

1. to force or drive (a fluid) into some passage, cavity, or chamber; esp., to introduce or force (a liquid) into some part of the body by means of a syringe, hypodermic needle, etc.
2. to fill by, or subject to, injection
3. to introduce (a missing feature, quality, etc.) to inject a note of humor into a story
4. to interject (a remark, opinion, etc.) as into a discussion

Etymology: < L injectus, pp. of injicere, to throw, cast, or put in < in-, in + jacere, to throw: see jet