Color Blocking is when a single article or outfit is composed of finite blocks of color. Some color blocking is layering colors rather than building blocks of color. There are several types of color blocking. Theres is monochromatic color blocking, color wheel color blocking, and black and white color blocking.
Hue: a color or shade
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Primary Colors: 3 colors that can't be formed by any other combination of colors  
(Red, Yellow, and Blue

Secondary Colors: Colors formed by mixing primary colors 
(Green, Orange, and Purple)

Tertiary Colors: Colors formed by mixing a primary and secondary color together

Complementary Colors:
Colors directly across from each other on the color wheel
Analogous Colors: 
Any three colors directly next to each other on the color wheel 
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Monochromatic Colors: All the colors (tints, tones, and shades) of a single hue

The Rule of Two-Thirds: 
“The most popular theory for combining colors is called the rule of two-thirds. How you achieve the rule of two-thirds starts by making an equilateral triangle (a triangle with 3 equal sides) on the color wheel… From there, you pick two of the three colors that the triangle touches. These colors will almost always harmonize together beautifully.” 
-Style Prompt