Chartreuse (the web color) is a color halfway between yellow and green that was named because of its resemblance to the green color of one of the French liqueurs called green chartreuse, introduced in 1764. Similarly, chartreuse yellow is a yellow color mixed with a small amount of green that was named because of its resemblance to the color of one of the French liqueurs called yellow chartreuse, introduced in 1838.

The term chartreuse was first used to refer to "a pale apple-green" in 1884. This was codified to refer to this brighter color when the X11 colors were formulated in 1987; by the early 1990s, they became known as the X11 web colors. The web color chartreuse is the color precisely halfway between green and yellow, so it is 50% green and 50% yellow. It is one of the tertiary colors of the HSV color wheel, also known as the RGB color wheel. Another name for this color is chartreuse green.