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

Many private insurance plans do not cover these drugs, forcing people who want the weekly injections to pay out of pocket. —Nicholas Florko, The Atlantic, 7 Nov. 2025

Even better, the pellets can be processed using standard injection-moulding machines — the same ones manufacturers already use for polystyrene test housings. —Neetika Walter, Interesting Engineering, 6 Nov. 2025

The current medicines, given by injection, will be available through TrumpRx without insurance at an average of $350 a month - down from around $500, which is what the companies offer patients buying directly today. —NPR, 6 Nov. 2025

Adame was convicted in the death of actress Cindyana Santangelo, who died shortly after receiving the silicone injections from Adame, The Los Angeles Times reports. —Madison E. Goldberg, PEOPLE, 6 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