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

Zepbound injection pen, March 28, 2024. —Annika Kim Constantino,jacob Pramuk, CNBC, 21 Nov. 2025

Florida’s lethal injections use a sedative, a paralytic and a drug that stops the heart, according to the Department of Corrections. —Greg Wehner, FOXNews.com, 21 Nov. 2025

Eswatini on Tuesday became the first African country to receive lenacapavir, the first twice-yearly HIV prevention injection hailed by global health officials as a game-changer in the fight against a virus that has killed tens of millions of people across the continent. —Farai Mutsaka, Fortune, 19 Nov. 2025

The studies also demonstrate that the product does, indeed, integrate into surrounding tissue and promote the growth of new fat cells and blood vessels for a limited time after injection. —Jolene Edgar, Allure, 19 Nov. 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