A Unary System is a numerical system that uses only one symbol to represent all values. In this system, the value of a number is determined by the count of the symbols used. For example, the number 5 would be represented as "11111," where each "1" signifies a single unit. This system is simple but not efficient for representing large numbers. Unary systems are often used in theoretical computer science and certain types of data encoding. They can also be found in tally marks, where each mark represents one unit. While useful for specific applications, unary systems are not practical for everyday calculations compared to more complex systems like the Decimal System or Binary System.