A "magic number" is a term frequently used in computer programming and refers to a specific value with special properties. There are several synonyms for this term that can be used interchangeably, including "unique number", "special number", "key value", and "critical value". Other related terms include "flag value", "control value", and "magic constant". These synonyms are often used to describe values that have a particular significance within a program, such as control parameters or numerical constants that affect the execution of certain functions. The use of these terms can also help to make programming code more easily understandable and accessible to other developers.