Cloisonnism is a term used to describe a style of art that employs the use of dark outlines to enclose areas of pure, vibrant colors. It was popularized by the French artist and designer, Émile Galle, during the Art Nouveau period. Often, the term cloisonnism is also used interchangeably with the term "stained glass style" or "mosaic style" due to the overlapping characteristics between the three styles. There are other synonymous terms that have also been used to describe cloisonnism, such as "encrusted enamel," "enameled shading," and "cloisonne shading." Despite the varying terminologies, the essence of cloisonnism remains the same - a vivid, bold and distinctive style that celebrates color and form.