A rainbow flag is a multi-colored flag consisting of stripes in the colors of the rainbow. The actual colors shown differ, but many of the designs are based on the traditional scheme of red, orange, yellow, green, blue and violet.
The use of rainbow flags has a long tradition; they are displayed in many cultures around the world as a sign of diversity and inclusiveness, of hope and of yearning. There are several independent rainbow flags in use today. The most widely known worldwide is the pride flag representing gay pride. The peace flag is especially popular in Italy and the cooperative flag symbolizes the international co-operative movement. It is also used by Andean people to represent the legacy of the Inca empire and Andean movements. (source)