ism

Etymology

From the suffix -ism (“belief”), particularly (in the 19th century) in the sense of "social movement". Compare phobia, from -phobia, sophy, from -sophy, itis, from -itis, and ana, from -ana.

noun

1. An ideology, system of thought, or practice that can be described by a word ending in -ism.
   […] his religion, his worship was like his daily bread to him; — which he did not take the trouble to talk much about; which he merely ate at stated intervals, and lived and did his work upon! This is Abbot Samson’s Catholicism of the Twelfth Century; — something like the Ism of all true men in all true centuries, I fancy! Alas, compared with any of the Isms current in these poor days, what a thing! 1843, Thomas Carlyle, chapter XV, in Past and Present, book 2
   If it gives way to sentimentalism, or sensibility, or political mysticism, or adopts an affectation of radicalism, or any other ism, or molds its institutions so as to round out to a more complete fulfillment somebody's theory of the universe, it may fall into an era of revolution and political insecurity […] 1887 August, W[illiam] G[raham] Sumner, “State Interference”, in North American Review
   An ism does not have to possess the fearful implements of state power to cut off a a deviant or heretical member. 1965, Bertram David Wolfe, Marxism, One Hundred Years in the Life of a Doctrine, page 357
   In his exposition, he has failed to achieve the identification of situation, theory, and policy necessary to create an ism. 1969, Walter E. Minchinton, Mercantilism; System Or Expediency?, page xi
   Isms in my opinion are not good. A person should not believe in an ism – he should believe in himself. 1986, John Hughes, Ferris Bueller's Day Off, spoken by Ferris Bueller (Matthew Broderick)
   It is important to distinguish between an ism and a mere generalization about group differences. Generalizations that have statistical validity are not isms. An ism assumes that the generalization applies to an individual. 1994, Kenneth Kaye, Workplace Wars and How to End Them, page 70
2. (specifically) A form of discrimination, such as racism or sexism.