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

With a single event, astronomers could explain how two rare occurrences — the injection of aluminum-26 and the formation of a new solar system — happened at virtually the same moment. —James Dinneen, Quanta Magazine, 2 Mar. 2026

Melvin Trotter, 65, was put to death by lethal injection last Tuesday for a 1986 murder of Virgie Langford, a Manatee County grocery-store owner. —Jim Turner, Sun Sentinel, 2 Mar. 2026

According to the Food and Drug Administration, the injections have not been approved and can cause serious injuries, disfigurement and even death. —Tim Fang, CBS News, 2 Mar. 2026

Children’s Hospital of Orange County reported providing one medical injection and four prescription refills for patients age 19 and older and 19 medication orders for 14 patients aged 18 and younger. —Paul Sisson, San Diego Union-Tribune, 2 Mar. 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