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

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

From Science Daily ● Aug. 14, 2026

The period saw a huge cash injection into theme parks, which remain a jewel in the company's crown, helping to push up the share price fivefold.

From Barron's ● Aug. 12, 2026

“Don’t be weird about this,” she said as she gave herself an injection.

From Salon ● Aug. 12, 2026

In the 1950s, Miller began making figurines — often of dinosaurs and space aliens — using plastic injection molding.

From Los Angeles Times ● Aug. 10, 2026

The pain of the injection was very, very bad.

From "The Hot Zone" by Richard Preston

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

“Use of monovalent vaccines also would increase the number of injections a child would need and increase the number of visits required to complete the vaccination series.”

From Los Angeles Times ● Aug. 12, 2026

Egg freezing involves stimulating the ovaries with hormone injections before mature eggs are surgically retrieved and preserved for possible future use through in vitro fertilization.

From Barron's ● Aug. 10, 2026

But when he instructed his staff to give the injections without telling patients they contained cancer cells, three young Jewish doctors refused, saying they wouldn’t conduct research on patients without their consent.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot

Related Words

• dose
• needle