What is a 'cameo' appearance in a comic book?

What is a 'cameo' appearance in a comic book?

Mark Zaid (Owner of Esquire Comics) gives expert video advice on: What are the different types of comic book covers? and more...

A cameo appearance in a comic book would be just a very quick appearance of a character in a particular comic book. Maybe they're on a page or in an actual segment sort of slot of the comic book, and they're there just their one day and gone the next.