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 idea to use carbon injection as a climate fix came a few years later from an Italian physicist named Cesare Marchetti, who suggested disposing of carbon deep in the ocean or underground. — Katie Worth, ProPublica, 30 Oct. 2026

Attackers first exploited an admin authentication bypass to gain access, then used a separate SQL injection flaw to steal credentials and finally leveraged two additional issues to achieve remote code execution and plant a persistent web shell. — Rohit Dhamankar, Forbes.com, 30 Oct. 2026

Medical and lethal injection experts have focused on the possibility that a problem with the IV line caused the drug to pool in her tissue rather than entering her bloodstream. — Kim Chandler, Chicago Tribune, 30 Oct. 2026

The injections work by blocking the release of acetylcholine, the neurotransmitter that tells muscles to contract. — Hanna Wickes, Charlotte Observer, 29 Oct. 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