Monochromatic colors refer to a range of hues that are derived from one single color. In other words, these colors have the same color tone but differ in their saturation and lightness levels. For example, if you choose blue as your base color, all shades of blue - from pale blue to navy blue- would be considered monochromatic colors. Monochromatic colors are often used in fashion, interior design, and graphic art because they create a sense of harmony and balance within the composition.