An artist's tool is a paintbrush, which is a tool used by artists to apply paint to a surface. Paintbrushes come in a variety of shapes and sizes, and are made from different materials such as natural or synthetic bristles. They are used to create a variety of effects, from broad strokes to fine details. Paintbrushes are essential for creating artworks in many mediums, including oil, acrylic, watercolor, and gouache.