injection

noun

in·​jec·​tion in-ˈjek-shən How to pronounce injection (audio)
Synonyms of injectionnext
1
a
: an act or instance of injecting
b
: the placing of an artificial satellite or a spacecraft into an orbit or on a trajectory
also : the time or place at which injection occurs
2
: something (such as a medication) that is injected
3
: a mathematical function that is a one-to-one mapping compare bijection, surjection

Examples of injection in a Sentence

The medicine cannot be taken orally; it must be given by injection. an injection of a painkiller The struggling company needed an injection of cash.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
For years, the most effective psoriasis treatments meant regular biologic injections. — Leslie Baumann, Miami Herald, 3 Sep. 2026 The advancing gas front improves sweep efficiency by penetrating tight, unreached reservoir compartments that standard water-injection floods bypass during secondary extraction campaigns. — Aman Tripathi, Interesting Engineering, 2 Sep. 2026 The doctor on duty suggested an antibiotic injection to knock out his symptoms faster than a pill or over-the-counter syrup. — Betsy Joles, NPR, 2 Sep. 2026 New parents are also increasingly declining a Vitamin K injection for their infants. — Ruby Cramer, New Yorker, 31 Aug. 2026 See All Example Sentences for injection

Word History

First Known Use

15th century, in the meaning defined at sense 1a

Time Traveler
The first known use of injection was in the 15th century

Phrases Containing injection

Rhymes for injection

See All Rhymes for injection

Browse Nearby Words

injectant
injection
injection gneiss
See all Nearby Words

Cite this Entry

“Injection.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/injection. Accessed 6 Sep. 2026.

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Kids Definition

injection

noun
in·​jec·​tion in-ˈjek-shən How to pronounce injection (audio)
1
: an act or instance of injecting
2
: something (as a medical drug) that is injected

Medical Definition

injection

noun
in·​jec·​tion in-ˈjek-shən How to pronounce injection (audio)
1
a
: the act or an instance of injecting a drug or other substance into the body
b
: a solution (as of a drug) intended for injection (as by catheter or hypodermic syringe) either under or through the skin or into the tissues, a vein, or a body cavity
c
: an act or process of injecting vessels or tissues
also : a specimen prepared by injection
2
: the state of being injected : congestion see circumcorneal injection

More from Merriam-Webster on injection

Thesaurus: All synonyms and antonyms for injection

Britannica.com: Encyclopedia article about injection

Last Updated: - Updated example sentences
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