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

An injection of buprenorphine lasts a month but costs $1,630. —Andy Sheehan, CBS News, 1 May 2026

The same-day executions by lethal injection came about an hour and a half apart on Thursday, April 30. —Amanda Lee Myers, USA Today, 1 May 2026

For persistent symptoms, more advanced therapies are also available, including Botox injections into the bladder muscle and neuromodulation, which targets the nerves that control bladder function. —Lauryn Higgins, Flow Space, 1 May 2026

James Ernest Hitchcock, 69, was put to death by lethal injection Thursday evening at Florida State Prison in Starke for the rape and murder of his brother’s 13-year-old stepdaughter nearly 50 years ago. —Jim Turner, Miami Herald, 1 May 2026

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