pluralism (n.)

late 14c., originally in grammar (distinguished from singular), "containing or consisting of more than one," from Old French plurel "more than one" (12c., Modern French pluriel) and directly from Latin pluralis "of or belonging to more than one," from plus (genitive pluris) "more" (see plus). The noun meaning "a plural number" is from late 14c.

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.