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".
by xCOBRA_CLUTCHx March 29, 2004

by Happy love hit March 8, 2014

by audiodecoy April 4, 2005

A "rainbow party" is supposed to be a party where girls wear different shades of lipstick and suck a guy off. In actuality, it is a term invented by Oprah and no teen had heard of it until her show in 2004.
by C March 14, 2005

In the US, it is apparently a euphemism (or media-invented myth)for rather lewd naughtiness (see all other definitions). In the UK, it means jelly, ice-cream and dressing-up as Zippy, Bungle, Geoffrey, George, Rod, Jane or Freddy and singing "The Wheels on the Bus". The latter seems condusive to a much more satisfying experience.
Yank: Dude, I'm so emotionally crippled and shallow, I went to this badass Rainbow Party last night. Now I feel even more empty and my dick's kinda itchy.
Limey: I say, old bean, I had a Rainbow Party last week! We all had a beezer time, despite Bungle having eaten too much jelly and ice-cream.
Limey: I say, old bean, I had a Rainbow Party last week! We all had a beezer time, despite Bungle having eaten too much jelly and ice-cream.
by chris wheelie July 15, 2008

by Zuf April 8, 2008

To be so excited about something you almost shoot the gayest thing in the world out of your butt. Similar to pooping kittens.
by plaidtattoo February 10, 2009
