injection

noun

in·​jec·​tion in-ˈjek-shən 

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

Most flu vaccines currently used in the United States contain little to no thimerosal, but both the Food and Drug Administration and the CDC say there is no evidence low doses of thimerosal in vaccines cause harm other than minor reactions at the injection site, such as redness or swelling. —Mary Kekatos, ABC News, 26 June 2025

There is extensive data from the last quarter century proving that the antiseptic preservative is safe, with no harms identified beyond slight soreness at the injection site, but none of that data was presented during today's meeting. —ArsTechnica, 26 June 2025

Richard Gerald Jordan, a 79-year-old Vietnam veteran with PTSD, received a lethal injection at the Mississippi State Penitentiary in Parchman. —Louis Casiano, FOXNews.com, 25 June 2025

Lethal injection is the only method of execution after firing squads were abolished in 2011. —CNN Money, 25 June 2025

Word History

First Known Use

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

Phrases Containing injection

• fuel injection
• hypodermic injection
• injection molding

Rhymes for injection

• abjection
• advection
• affection
• bijection
• bisection
• collection
• complexion
• confection
• connection
• connexion
• convection
• correction

Kids Definition

injection

noun

in·​jec·​tion in-ˈjek-shən 

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 

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