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 $50-million injection from the DFC will be used only once Rainbow Rare Earths starts construction of its processing factory in Phalaborwa, anticipated in early 2027. —Michelle Gumede, Los Angeles Times, 19 Apr. 2026

Take the quiz here … LONGEVITY QUEST — Peptide injections may hit shelves with RFK Jr's push, FDA could ease restrictions. —FOXNews.com, 17 Apr. 2026

With the help of monthly B12 injections and five months of physical therapy, Tera began to regain her strength. —Rachel Roberts, Idaho Statesman, 17 Apr. 2026

Four days after the trans-lunar injection engine firing, Wiseman and his crewmates reached a point in space 248,655 miles from Earth, the previous record for the farthest any human has flown into deep space. —William Harwood, CBS News, 16 Apr. 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