injection

American  

[in-jek-shuhn] / ɪnˈdʒɛk ʃən /

noun

• injections
  plural

1. the act of injecting.

2. something that is injected.

3. a liquid injected into the body, especially for medicinal purposes, as a hypodermic or an enema.

4. state of being hyperemic or bloodshot.

5. Mathematics. a one-to-one function.

6. Also called insertion.  Aerospace. the process of putting a spacecraft into orbit or some other desired trajectory.

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injection British  

/ ɪnˈdʒɛkʃən /

noun

1. fluid injected into the body, esp for medicinal purposes

2. something injected

3. the act of injecting

4. 1. the act or process of introducing fluid under pressure, such as fuel into the combustion chamber of an engine

   2. ( as modifier )

      injection moulding

5. maths a function or mapping for which f( x ) = f( y ) only if x = y See also surjection bijection

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injection Scientific  

/ ĭn-jĕk′shən /

1. A substance that is introduced into a organism, especially by means of a hypodermic syringe, as a liquid into the veins or muscles of the body.

2. A function that maps each member of one set (the domain) to exactly one member of another set (the range).

3. Compare bijection surjection

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Other Word Forms

Derived Forms

• reinjection
  noun
• superinjection
  noun
• injective
  adjective
• postinjection
  adjective

Inflected Forms

Nouns

• injections
  plural

Etymology

Origin of injection

First recorded in 1535–45, injection is from the Latin word injectiōn- (stem of injectiō ). See inject, -ion

Explanation

An injection is a shot, or a dose of medicine given by way of a syringe and a needle. When you get jabbed in the arm with a tetanus vaccine, that's an injection. The medical kind of injection forces a small amount of a drug under the skin or directly into a muscle. Other injections are similar in that they involve a liquid being forced by pressure, like the fuel injection in a car, which pushes gasoline directly into the engine. Since the 1600s, injection has been used to mean "forcing a fluid into a body," from the Latin inicere, "to throw in" or "to throw on."

Example Sentences

See Examples For:

injection injections

ET, which are expected to show a smaller-than-average injection into storage.

From The Wall Street Journal ● Aug. 20, 2026

It will be his third bullpen since receiving an Orthovisc injection in his left knee at the beginning of the All-Star break to lubricate the joint, but his second since restarting his throwing program.

From Los Angeles Times ● Aug. 18, 2026

When laboratory mice experience brain damage, e.g., from an injection, Jan Deussing repeatedly notices the same response.

From Science Daily ● Aug. 14, 2026

Distressed vets administered a glucose injection -- the only option, given that the cause of the ailment remains unknown -- to the 11-year-old male, known as Genghis Khan, who was struggling to breathe.

From Barron's ● Aug. 13, 2026

Finally, when the sky grew dark, Sister Gladys gave her an injection to make her sleep and to lessen the pain of the broken wrist.

From "A Girl Named Disaster" by Nancy Farmer

"Other common treatments for knee osteoarthritis include strengthening the thigh muscles, using knee braces, taking anti-inflammatory medications, getting cortisone and other injections, and sometimes having knee replacement surgery."

From Science Daily ● Aug. 20, 2026

Still, new pill forms of the drugs, which previously had been administered via injections, and expanding health-plan coverage are set to make them more accessible and affordable.

From The Wall Street Journal ● Aug. 19, 2026

In addition, Cassidy argued that the changes could turn two MMR shots into six individual injections — while requiring additional trips to the doctor’s office.

From Salon ● Aug. 16, 2026

Last summer, Representative Sara Jacobs would run up to her office to give herself injections of hormones before rushing back to Congress for a session with her fellow lawmakers.

From BBC ● Aug. 15, 2026

I could remotely conceive surprising him once, for an instant, the way his mother had been when she was captured— but to surprise him long enough to give him six consecutive injections?

From "Life of Pi" by Yann Martel

Related Words

• dose
• needle