A person who loves the color blue is often referred to as "cyanophile" or "ceruleanophile." The term "cyanophile" comes from the word "cyan," which is a shade of blue-green, while "ceruleanophile" is derived from "cerulean," which is a deep sky-blue color. Both terms are not commonly used in everyday language, but they are occasionally employed to describe individuals who have a strong affinity or preference for the color blue. In more informal settings, someone who loves the color blue might simply be called a "lover of blue" or a "blue enthusiast."