The primary colors are the fundamental building blocks of all colors. They're like the atomic elements of color theory, and when combined in specific ratios, they create the entire spectrum of colors we see before us.
Red, yellow, and blue are the three primary colors. They're like the holy trinity of color theory, and when mixed together in the correct proportions, they form:
They're like the awkward cousins of the primary colors. They're still fun to play with, but you might not want to invite them to family reunions.
They're like the distant aunts of the color family. They're a bit weird, but still interesting to talk to.