For the Huichol (wee-chol), a 'Nierika' is a picture, an appearance, or a sacred representation. The term nierika is etymologically rooted in the verb nieriya, "to see". However the definition is pretty watered down and loses a bit of depth when considering the metaphysical significance tied to it by the Huichol.
Traditional Nierika Yarn Painting, Huichol yarn painting by master artist Cresencio Perez Robles, eye at the center of the known universe, colorful, living art, induced by ingestion of peyote