also multi-cultural, of a society, "consisting of varied cultural groups," by 1941; see multi- "many"+ culture (n.) + -al (1). At first often in a Canadian context. Picked up by U.S. education writers 1980s; widespread popular use from c. 1990.
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
<a href="https://www.etymonline.com/word/multiculturalism">Etymology of multiculturalism by etymonline</a>
Harper, D. (n.d.). Etymology of multiculturalism. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/multiculturalism