Red, yellow and blue are the three primary colors. These colors are used in combination to create all other colors. The secondary colors are green, orange and purple. The primary and secondary colors make up the color wheel.
The tertiary colors are the colors that lie between the primary and secondary colors. These include yellow-green, blue-green, red-violet and others.
The color wheel is used to determine color harmony. Colors that are directly across from each other on the color wheel are complementary colors--for example, blue and yellow. Analogous colors are a series of three colors/shades that appear side-by-side on the color wheel, such as red, red-orange and orange, for example.
Colors are often further divided into warm and cool categories. Warm colors occupy roughly the right side of the color wheel, from red to yellow-green; cool colors are those on the left side, from reddish purple to green.
Colors like white, black, gray and brown are considered neutral colors.
The term "hue" simply refers to the color (blue, red, green, etc.). "Saturation" is the intensity level of the color, so a very pronounced color is said to have high saturation, and a dull or muted color has low saturation. "Value" refers to the color's brightness and is measured on a scale from one to 10, with the blackest beginning at one.