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

That’s higher than results seen with both the Wegovy injection and pill as well as Eli Lilly’s oral drug in separate trials. —Annika Kim Constantino, CNBC, 10 Jan. 2026

The team used vacuum or micro-injection techniques The team with LLNL’s Nuclear and Chemical Sciences (NACS) Division, developed the radiochemical techniques to purify target material. —Prabhat Ranjan Mishra, Interesting Engineering, 9 Jan. 2026

Some said the elimination of a key source of demand could push down prices, while others cautioned the move would likely have little effect in those places, since an injection of new supply has already helped ease price pressures in many of those areas. —Max Zahn, ABC News, 9 Jan. 2026

One of the solutions that came out of meetings with both was the use of a drug called Beyfortus, an antibody injection given to newborns and young children to help treat RSV. —Jackson Thompson, FOXNews.com, 9 Jan. 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