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

Mills was executed by lethal injection, and Grayson and Smith died by an execution method using nitrogen gas. —Abigail Brooks, NBC news, 25 Sep. 2025

The drugmaker said earlier this week that its CT-388 weight loss injection was entering a phase III trial — the final stage before a company can seek regulatory approval — marking the latest development in Roche's nascent but fast-growing pipeline of treatments for obesity and related conditions. —Karen Gilchrist, CNBC, 25 Sep. 2025

The majority of councilors present for the meeting disagreed with the sponsors, and preferred to describe safe injection sites as overdose prevention centers. —Gayla Cawley, Boston Herald, 25 Sep. 2025

Staff administered Tylenol and an injection, but his condition did not improve. —Billal Rahman, MSNBC Newsweek, 24 Sep. 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