[myoo r-uh-liz-uh m]
noun (sometimes initial capital letter)
  1. an artistic movement identified chiefly with the Mexican painters José Orozco, Diego Rivera, and David Siqueiros and exemplified by their grand-scale, narrative murals on humanitarian, social, and political themes.

Origin of muralism

mural + -ism; compare Spanish muralismo Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018