Meaning

noun a school of painters who used a technique of painting with tiny dots of pure colors that would blend in the viewer's eye; developed by Georges Seurat and his followers late in 19th century France

noun a genre of painting characterized by the application of paint in dots and small strokes; developed by Georges Seurat and his followers in late 19th century France

originFrom French pointillisme, from pointiller (“to dot, to mark with points”), from point (“dot, point”).

Etymology from Wiktionary, CC BY-SA 3.0