The word 紫色 is formed by directly combining the character 紫 (zǐ), which means "purple", with the character 色 (sè), which means "color". It is a straightforward, descriptive compound where the specific hue is named first, and then the general category of "color" is added to it, creating a complete and concrete concept for "the color purple". This formation is based on a simple, logical association rather than a complex linguistic rule.