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

In an Instagram video posted on July 16, Conner, who has been married to the Chicago star for 10 years, can be seen getting the injection done in areas around his forehead. — Michelle Lee, PEOPLE, 17 July 2026

After hearing an emotional testimony, Judge Delucchi upheld the jury's suggestion of the death penalty, sentencing Scott to death by lethal injection. — Erin Jensen, USA Today, 17 July 2026

The biggest practical difference is the form — a daily pill instead of an injection every two to four weeks — which may appeal to people who have fear of needles or find injection schedules challenging to keep up with. — Robert Glatter, Forbes.com, 17 July 2026

If Apple's appeal fails, Danaher shareholders get a very nice cash injection that isn't factored into the stock price today. — Harvey Stober, CNBC, 16 July 2026

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