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

Beyond removing the psychological and practical barrier of injections, oral formulations are not reliant on syringes or refrigeration and are cheaper to manufacture. — Perdita Nouril, Vogue, 21 Aug. 2026

Giving an agent broad, unmonitored access to an entire database ecosystem invites severe security vulnerabilities, prompt injection exploits and catastrophic hallucination loops. — Barney Krishnan, Forbes.com, 21 Aug. 2026

Marte received an injection, Hazen said, and could return as soon as the minimum stint has been reached. — Johnny Flores Jr, New York Times, 21 Aug. 2026

Drugs became a central part of their relationship, and early on, Watts brought McCollough to a practitioner for an intramuscular ketamine injection. — Cheyenne Roundtree, Rolling Stone, 20 Aug. 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