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

Reflection Injection: Reflection, a startup backed by chip giant Nvidia that is leading an effort to create freely available U.S.

From The Wall Street Journal • Mar. 29, 2026

His most recent book is "Lethal Injection and the False Promise of Humane Execution."

From Salon • May 20, 2025

Using a high-powered microscope system designed by Baylink called the Chemosensory Injection Rig Assay, the researchers simulated intestinal bleeding by injecting microscopic amounts of human serum and watching as the bacteria navigated toward the source.

From Science Daily • Apr. 16, 2024

Injection of epinephrine is used to treat serious and sometimes life-threatening allergic reactions to foods, medications, bee stings and other causes.

From Reuters • Apr. 17, 2023

Injection of Iodoform.—This is carried out on the same lines as have been described for tuberculous abscess.

From Manual of Surgery Volume First: General Surgery. Sixth Edition. by Thomson, Alexis

Related Words

• dose
• needle