Tertiary colors are produced by mixing primary and secondary colors. The three primary colors are red, yellow, and blue. The three secondary colors are orange, green, and violet. When a primary color is mixed with a secondary color, the result is a tertiary color. For example, when red is mixed with orange, the result is red-orange. When yellow is mixed with green, the result is yellow-green. And when blue is mixed with violet, the result is blue-violet.

There are six tertiary colors in total:

* Red-orange

* Yellow-orange

* Yellow-green

* Blue-green

* Blue-violet

* Red-violet

Tertiary colors are often used to add variety and interest to a color scheme. They can also be used to create a sense of harmony or contrast.