[ in-jek-shuh n ]
/ ɪnˈdʒɛk ʃən /


the act of injecting.
something that is injected.
a liquid injected into the body, especially for medicinal purposes, as a hypodermic or an enema.
state of being hyperemic or bloodshot.
Mathematics. a one-to-one function.
Also called insertion. Aerospace. the process of putting a spacecraft into orbit or some other desired trajectory.

Origin of injection

First recorded in 1535–45, injection is from the Latin word injectiōn- (stem of injectiō). See inject, -ion


post·in·jec·tion, adjectivere·in·jec·tion, nounsu·per·in·jec·tion, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for injection

British Dictionary definitions for injection

/ (ɪnˈdʒɛkʃən) /


fluid injected into the body, esp for medicinal purposes
something injected
the act of injecting
  1. the act or process of introducing fluid under pressure, such as fuel into the combustion chamber of an engine
  2. (as modifier)injection moulding
maths a function or mapping for which f(x) = f(y) only if x = ySee also surjection, bijection

Derived forms of injection

injective, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for injection

[ ĭn-jĕkshən ]


The act of injecting a substance into a tissue, vessel, canal, or organ.
Something that is injected, especially a dose of liquid medicine injected into the body.
Congestion or hyperemia.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for injection

[ ĭn-jĕkshən ]

A substance that is introduced into a organism, especially by means of a hypodermic syringe, as a liquid into the veins or muscles of the body.
A function that maps each member of one set (the domain) to exactly one member of another set (the range). Compare bijection surjection.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.