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 deal includes both a capital injection and line of credit designed to fuel the prodco’s expansion. —Naman Ramachandran, Variety, 2 June 2025

Current data showed that the therapy's effects waned after 4–6 weeks due to declining concentrations of the medicine, requiring repeat injections. —William A. Haseltine, Forbes.com, 2 June 2025

For women, there are birth-control pills, intrauterine devices (IUDs), implants, injections, patches, vaginal rings and tubal ligation. —Dr. Jamin Brahmbhatt, CNN Money, 1 June 2025

Even dosing people with EPO directly with injections may not prevent altitude sickness or improve performance at high elevation, Subudhi says. —Stephanie Pappas, Scientific American, 29 May 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