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

Injection rates in CO2 projects have been "much, much lower" than wastewater injection rates in the 2000s and 2010s, said Juanes, which might explain why moderate-sized induced seismicity hasn't been seen at carbon sequestration projects.

From Science Daily • May 8, 2024

Smith's Stratospheric Aerosol Injection Lofter would heft 15.7 tons of aerosol to a height of 20 kilometers every flight.

From Scientific American • Sep. 20, 2023

Whether a Dog may be kept alive without eating by the frequent Injection of the Chyle of another, taken freshly from the Receptacle, into the Veins of the Recipient Dog?

From Philosophical Transactions of the Royal Society - Vol 1 - 1666 Giving some Accompt of the present Undertakings, Studies, and Labours of the Ingenious in many considerable parts of the World by Oldenburg, Henry

Related Words

• dose
• needle