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

Executions are on hold in Idaho as the state prison system remodels its execution chamber in the transition from lethal injection to a firing squad as the lead method. —Kevin Fixler september 5, Idaho Statesman, 5 Sep. 2025

Studies have found that people who used tirzepatide injections such as Zepbound lost more weight and were more likely to reach specific weight loss targets than those using semaglutide medications such as Wegovy. —Deidre McPhillips, CNN Money, 5 Sep. 2025

The injection molding process begins with the user pouring a liquid elastomer mixture into the injection chamber. —New Atlas, 3 Sep. 2025

Novo Nordisk last week said Wegovy cut the risk of heart attack, stroke or death by 57% versus Eli Lilly's weight loss injection Zepbound in a real-world comparison of the rival medicines in patients with obesity and cardiovascular diseases but not diabetes. —Annika Kim Constantino,ashley Capoot, CNBC, 3 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