in·​jec·​tion | \ in-ˈjek-shən \

Definition of injection

1a : 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.
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Recent Examples on the Web

Photo: Dana Verkouteren/Associated Press Justice Kavanaugh remained silent while Mr. Hochman debated the fine points of lethal injection with other justices and argued the feasibility of killing him with poison gas. Jess Bravin, WSJ, "Kavanaugh Questions Death-Penalty Method in Missouri Case," 6 Nov. 2018 Clark was set for lethal injection Wednesday evening, Sept. 26, 2018, for the 1998 slaying of a former roommate, 20-year-old Christina Muse of Tyler. Fox News, "Texas executes man in the torture, drowning of ex-roommate," 28 Sep. 2018 Lethal injection was once the overwhelming choice for states executing prisoners. David Montero,, "Nevada plans to execute inmate next week using controversial paralytic drug," 4 July 2018 Otherwise, your doctor can walk you through your options, including stronger drugs like prescription anti-inflammatories and muscle relaxants, along with steroid injections to do away with excessive inflammation, according to the Mayo Clinic. Korin Miller, SELF, "This Is the Number One Sign You Have Sciatica," 29 Aug. 2018 Following her daughter’s death in 2015, LeGere has worked with legislators to provide police officers with life-saving epinephrine auto injections, the Chicago Tribune reports. Serena Sonoma, Teen Vogue, "Annie LeGere Law Allows Illinois Police to Carry EpiPens," 1 Aug. 2018 The following month, a second doctor who evaluated him recommended that Rice be treated with injections to his hip. John Sowell, idahostatesman, "Motorist dragged from car testifies that police actions led to permanent injuries," 23 Apr. 2018 Hurley’s presence fixes some problems, but not all, immediately with injections of hope and intensity. Mike Anthony,, "UConn Insider: Dan Hurley The Fire UConn Basketball Needed," 23 Mar. 2018 Traywick has continued with public injections, treating himself for herpes at a biohacking conference earlier this month. David Grossman, Popular Mechanics, "People Are Treating Themselves With DIY Gene Therapies and the Government Is Getting Worried," 8 Feb. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'injection.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of injection

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

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Statistics for injection

Last Updated

14 Feb 2019

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Time Traveler for injection

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

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More Definitions for injection



English Language Learners Definition of injection

: the act or process of forcing a liquid medicine or drug into someone or something by using a special needle
: the act or process of forcing a liquid into something
: the addition of something (such as money) that is needed to support something


in·​jec·​tion | \ in-ˈjek-shən \

Kids Definition of injection

: an act or instance of forcing a fluid (as a medicine) into a part of the body by using a special needle Insulin can be given by injection.


in·​jec·​tion | \ in-ˈjek-shən \

Medical Definition of injection

1a : 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

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More from Merriam-Webster on injection

Rhyming Dictionary: Words that rhyme with injection

Spanish Central: Translation of injection

Nglish: Translation of injection for Spanish Speakers

Britannica English: Translation of injection for Arabic Speakers Encyclopedia article about injection

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