Spot color is a term used to refer to a single, solid color that is printed using a single screen. This is often used for printing simple designs with just a few colors. Process color, on the other hand, refers to the printing of full-color graphics using a combination of four primary colors (cyan, magenta, yellow, and black). This is done by creating separate screens for each color and printing them one at a time, with the colors overlapping to create a full-color image.