[in-fek-shuh n]
  1. an act or fact of infecting; state of being infected.
  2. an infecting with germs of disease, as through the medium of infected insects, air, water, or clothing.
  3. an infecting agency or influence.
  4. an infectious disease: Is this infection very dangerous?
  5. the condition of suffering an infection.
  6. corruption of another's opinions, beliefs, moral principles, etc.; moral contamination.
  7. an influence or impulse passing from one to another and affecting feeling or action.
  8. Grammar. (in Celtic languages) assimilation in which a vowel is influenced by a following vowel or semivowel; umlaut.

Origin of infection

1350–1400; Middle English infeccio(u)n < Late Latin infectiōn- (stem of infectiō). See infect, -ion
Related formsnon·in·fec·tion, nounpost·in·fec·tion, adjectivepre·in·fec·tion, nounre·in·fec·tion, nounsub·in·fec·tion, noun
Can be confusedinfection inflection Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for subinfection


  1. invasion of the body by pathogenic microorganisms
  2. the resulting condition in the tissues
  3. an infectious disease
  4. the act of infecting or state of being infected
  5. an agent or influence that infects
  6. persuasion or corruption, as by ideas, perverse influences, etc
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

Word Origin and History for subinfection



late 14c., "infectious disease; contaminated condition;" from Old French infeccion "contamination, poisoning" (13c.) and directly from Late Latin infectionem (nominative infectio), noun of action from past participle stem of Latin inficere (see infect). Meaning "communication of disease by agency of air or water" (distinguished from contagion, which is body-to-body communication), is from 1540s.

Online Etymology Dictionary, © 2010 Douglas Harper

subinfection in Medicine


  1. A secondary infection occurring in a person exposed to and successfully resisting another infectious disease.


  1. Invasion by and multiplication of pathogenic microorganisms in a bodily part or tissue, which may produce subsequent tissue injury and progress to overt disease through a variety of cellular or toxic mechanisms.
  2. An instance of being infected.
  3. An agent or a contaminated substance responsible for one's becoming infected.
  4. The pathological state resulting from having been infected.
  5. An infectious disease.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

subinfection in Science


  1. The invasion of the body of a human or an animal by a pathogen such as a bacterium, fungus, or virus. Infections can be localized, as in pharyngitis, or widespread as in sepsis, and are often accompanied by fever and an increased number of white blood cells. Individuals with immunodeficiency syndromes are predisposed to certain infections. See also infectious disease opportunistic infection.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

subinfection in Culture


Invasion of the body or a body part by a pathogenic organism, which multiplies and produces harmful effects on the body's tissues.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.