Blonde Girl Shows Off In The Purple Bed

In the US and United Kingdom militaries, purple refers to programs or assignments that are "joint", i. e., that are not confined to a single service such as the army or navy, but apply to the entire defense establishment. In the Canadian Forces they are known as purple trades. Assignment to one or more joint billets is required for promotion to flag rank (Rear Admiral and higher) in the U.S. Navy. Officers in joint billets are sometimes referred to as "wearing purple" (the phrase is purely metaphorical as there are no purple uniforms in the U.S. armed forces, UK armed forces or Canadian Forces.)
During and before World War II, the Japanese used a code known as PURPLE or the Purple Code. The Allies' military successes in the Pacific theater depended on the fact that the Japanese did not know that Allied cryptographers had broken the code.
The Purple Heart is a US military decoration awarded in the name of the President of the USA to those who have been wounded or killed while serving on or after April 5, 1917 with the U.S. military.