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

Tennessee law holds that those who committed crimes before 1999 can choose between being put to death by lethal injection or the electric chair. —Evan Mealins, Nashville Tennessean, 3 Oct. 2025

For three months, starting in April 2024, Williams received a daily injection of the drug followed by one hour of physical therapy, which included hand exercises and walking with a harness on a flat track or treadmill. —Angelica Stabile, FOXNews.com, 3 Oct. 2025

Via pipelines, the supercritical CO2 is delivered to injection wells where it’s stored permanently in deep underground geological formations, generally one to two kilometers deep. —Tejasri Gururaj, Interesting Engineering, 3 Oct. 2025

At the same time, Angel City’s midfield is receiving a major injection of talent. —Phil Hay, New York Times, 1 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