A range check is a method used in programming and data validation to ensure that a value falls within a specified set of limits. For example, if a program requires a user to enter their age, a range check would verify that the input is between 0 and 120. This helps prevent errors and ensures that the data is reasonable and usable. Range checks are commonly applied in various fields, including software development, data entry, and database management. By implementing range checks, developers can enhance the reliability of their applications and protect against invalid or harmful data inputs.