When mixed together, green and yellow combine to create a color called yellow-green, according to Color Matters. The color result can also be manipulated by adding varying amounts of the two colors. For example, if more green is used, the color created would be more green-yellow than yellow-green.
The color yellow-green is considered a tertiary color, says Color Matters. Tertiary colors are created by mixing a primary and secondary color together. In this case, yellow is the primary color and green, which is created by mixing blue and yellow, is the secondary color. Other tertiary colors include red-orange, red-purple and blue-purple, which is also called blue-violet.