Painting technique whereby tones and hues are obtained by applying regular small dots or touches of unmixed pigment on the canvas so that they combine optically. The French critic Félix Fénéon coined the term "peinture au point" in 1886 after seeing Seurat's "La Grande Jatte." Paul Signac offered the alternative term of "divisionism" in his book "D'Eugène Delacroix au Néo-Impressionnisme (1899), although in modern usage "pointillism" is reserved for the technique involving dots applied in a controlled manner, while "divisionism" refers to use of marks of unmixed color in Italian painters’ works.

Source: Art & Arcihtecture Thesaurus

http://vocab.getty.edu/page/aat/300067450