The number "555-1234" is a fictional telephone number commonly used in movies, television shows, and other forms of media. It is part of the North American Numbering Plan, where the "555" prefix is designated for use in entertainment to avoid using real phone numbers. This specific format helps prevent viewers from accidentally dialing a real number that could belong to someone else. The use of "555" has become a recognizable trope, allowing creators to maintain a level of realism while ensuring privacy and avoiding unwanted calls.