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

Catcher Will Smith, on the other hand, has not returned to baseball activities since receiving an injection to address his neck injury. — Maddie Lee, Los Angeles Times, 28 June 2026

For five days leading up to his donation, Siqueiros-Lasky will receive injections that spike his blood stem cell production, which can cause bone and muscle aches. — Rylan Digiacomo-Rapp, The Orlando Sentinel, 27 June 2026

The update adds optional safeguards like prompt injection detection and explicit user confirmation. — Paul Monckton, Forbes.com, 27 June 2026

The medications were initially marketed as injections, but on April 1, 2026, the Food and Drug Administration approved the second new oral medication, Foundayo, from Eli Lilly. — Stephanie Stephens, USA Today, 26 June 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