1802, "pertaining to or of the nature of a (French) commune;" 1843 as "of or pertaining to a community," from French communal (Old French comunal, 12c.), from Late Latin communalis, from communa, from Latin communis (see commune (n.)). A revival of an obsolete Middle English adjective meaning "common, unanimous" (late 15c.). Related: Communality; communalization.
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.
Others are reading
Definitions of communalism from WordNet
the practice of communal living and common ownership;
loyalty and commitment to the interests of your own minority or ethnic group rather than to society as a whole;