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

The researchers are planning for larger trials to evaluate the outcomes in specific groups of people, comparing low-dose radiation injections with medication regimens. —Angelica Stabile, FOXNews.com, 17 Oct. 2025

She's also detailed her regular Botox injections and notably received an earlobe reduction in 2018, which was filmed in an episode of Keeping Up with the Kardashians. —Rachel Raposas, PEOPLE, 17 Oct. 2025

The pens are interchangeable with glargine, the generic alternative for Lantus, a once-a-day injection that regulates blood sugar. —Calmatters, Mercury News, 16 Oct. 2025

Missouri executes 1st inmate of the year Missouri executed Lance Shockley, 48, by lethal injection for the 2005 murder of 37-year-old Sgt. —Amanda Lee Myers, USA Today, 15 Oct. 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