Just like with any sport, area of study or specialized job, there is a language that defines it.
Dog showing and dog fancy is no different.

Show dog- This can be a dog that intends to be shown, has been shown, is retired from showing,
or is shown alot or a little. There are a variety of venues to show, there is American Kennel Club,
United Kennel Club, the International Kennel Club as well as Canadian Kennel Club. There are clubs in
Europe and south America as well that have titles. Any dog can compete at any venue as long as they
get registered in that club.
Link to AKC dog showing for beginners