[ iz-uhm ]
/ ˈɪz əm /
Save This Word!

a distinctive doctrine, theory, system, or practice: This is the age of isms.
Should you take this quiz on “shall” versus “should”? It should prove to be a quick challenge!
Question 1 of 6
Which form is used to state an obligation or duty someone has?

Origin of ism

Extracted from words with the suffix -ism

Other definitions for ism (2 of 2)


a suffix appearing in loanwords from Greek, where it was used to form action nouns from verbs (baptism); on this model, used as a productive suffix in the formation of nouns denoting action or practice, state or condition, principles, doctrines, a usage or characteristic, devotion or adherence, etc. (criticism; barbarism; Darwinism; despotism; plagiarism; realism; witticism; intellectualism).
Compare -ist, -ize.

Origin of -ism

From Greek -ismos, -isma noun suffixes, often directly, often through Latin -ismus, -isma, sometimes through French -isme, German -ismus (all ultimately from Greek )
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use ism in a sentence

British Dictionary definitions for ism (1 of 3)

/ (ˈɪzəm) /

informal, often derogatory an unspecified doctrine, system, or practice

British Dictionary definitions for ism (2 of 3)


abbreviation for
interstellar medium

British Dictionary definitions for ism (3 of 3)


suffix forming nouns
indicating an action, process, or resultcriticism; terrorism
indicating a state or conditionpaganism
indicating a doctrine, system, or body of principles and practicesLeninism; spiritualism
indicating behaviour or a characteristic qualityheroism
indicating a characteristic usage, esp of a languagecolloquialism; Scotticism
indicating prejudice on the basis specifiedsexism; ageism

Word Origin for -ism

from Old French -isme, from Latin -ismus, from Greek -ismos
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 ism


Action, process; practice:vegetarianism.
Characteristic behavior or quality:puerilism.
State; condition; quality:senilism.
State or condition resulting from an excess of something specified:strychninism.
Doctrine; theory; system of principles:Darwinism.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.