RED, the color of blood, has been a symbol of life from earliest times. Prehistoric men and women used flaming red fires to cook, to scare away wild animals, and to stay warm. For these reasons, red was very important. So after black and white, red was the next color to be named. The English color word red can be traced back through Old English, Latin, and Sanskrit to its Indo-European roots.
Our eyes see red as the strongest color, making red objects stand out and appear to be closer than objects of other colors. Because red is somewhat rare in nature, it catches our eye and gets a reaction. This is why we use red for danger signs.