The new (circa 2002) 20 dollar bills that is siginfied by the pink and blue ink which has been added to the usual green and black. Due to the "flamboyant" color scheme of the newly circulated bills, the term "rainbow" was given to the twenty dollar bills. Not unlike the term "big face twenties".
"Hey cashier, why doesnt this rainbow twenty doesnt work in your Sprint bill pay machine?"
by xCOBRA_CLUTCHx March 29, 2004