Men's hairstyle that consists of short or shaved sides with the top of the head cut so it appears to be flat.
Famous people with a flat-top:
Ed Harris (in Apollo 13)
Nick Cassavetes (in The Astronaut's Wife)
Jake Busey (in Starship Troopers)
Bruce Willis (in The Jackal)
Jim Carrey (in Me, Myself & Irene)
Steve Timmons (Olympic volleyball medalist)