1) The surface on which a painter mixes his paint. Video here.

Palette used by the Dutch painter Vincent van Gogh (1853-1890). Van Gogh Museum, Amsterdam.

2) The range of colors typically used by an artist.

3) Cosmetic palettes are stone artifacts originally used in Predynastic Egypt to grind and mix materials for cosmetics. In the late fourth millennium BCE extra-large palettes, like the famous Palette of Narmer, appear to have lost their original function and became commemorative and/or ceremonial objects.

The Two Dog Palette. From Hierakonpolis, Egypt. Siltstone. Predynastic. Ca. 3300–3100 BCE. Ashmolean Museum, Oxford, UK.