Why purple? There’s a tradition in the military referring to the color purple. One use of the color involves the phrase “purple suit” which can refer to a military activity or organization that includes civilians and/or multiple branches of the military. Purple also indicates that all branches of the military are supported. All the service colors are represented including Air Force blue, Army green, Navy blue, Marine red, and Coast Guard blue which is said to combine for the mutual benefit of all into the color purple.