What does "blue" mean besides being a color?

Its blue is the coldest color. Blue is so pure that it is usually associated with ocean, sky, water and universe. Pure blue shows a kind of beauty, calmness, reason, tranquility and vastness. Blue has a rational and accurate image because of its calm characteristics. In commercial design, most commodities or corporate images that emphasize technology and efficiency choose blue as the standard color and corporate color, such as computers, cars, photocopiers and photographic equipment. In addition, blue also represents melancholy, which is influenced by western culture. This image is also used in literary works or commercial designs with emotional appeals. In many countries, police uniforms are blue. Police and ambulance lights are usually blue. Because blue has the meaning of courage, calmness, reason and never giving up. Many air force and navy uniforms are blue. Generally, the air force is sky blue and the navy is dark blue. Blue-collar workers generally refer to manual workers in factories. The name comes from the blue overalls that workers usually wear to work. In contrast, white-collar workers generally refer to office workers and generally wear white shirts. In Islam, blue is a pure color. European aristocrats are usually called "aristocrats". Some people think the name comes from their pale skin. In the west, blue is generally the color of boys, and pink is generally used by girls. Boys' clothes, toys, strollers, etc. Usually light blue. Interestingly, this habit only started after the First World War. Before that, blue was the color of girls and pink was the color of boys. So gay men used to be called "blue" in the west. The Blue Sox Club refers to a private gathering of cultural circles at that time. Because the vast majority of people attending such parties are women, and women at that time could not enter the university. The word "blue socks" soon became the goal of women, so it was given a discriminatory meaning. In Britain, the wedding custom requires each bride's dowry as follows: "some old, some new, some borrowed, some blue." (Something old, something new, something borrowed, something blue-loyalty) Blue hour is very popular in America and Britain. It refers to the time after work, that is, the time to relax. Blue also means beauty, freshness, tranquility, melancholy, openness and calmness! Luescher, a color test psychologist, analyzed the relationship between color and personality. Blue is the symbol of the ocean. Represents calmness and femininity. People who like blue are calm and upright, attach great importance to the trust relationship between people, take care of people around them, and be polite to others. Blue represents a broad mind, a spirit of never giving up and a harmonious world.