What is the term used to describe the lightness or darkness of a color?

The term that refers to the lightness or darkness of a color is "shade." In color theory, shade is created when black is added to a hue, which darkens the original color. This concept is essential in various fields, such as art, design, and fashion, as it helps in creating contrast and depth in visual compositions. Understanding shades allows individuals to manipulate colors effectively to achieve desired effects or to enhance aesthetics in their work.

The other terms provided do not accurately describe the relationship between lightness and darkness in a color. "Hue" refers to the dominant color family, such as red or blue, without considering its lightness. "Illusion" relates more to visual perception and how colors can affect the way we see other colors. "Style" pertains to the manner in which something is expressed or designed, rather than its color characteristics.