exception

An exception is something that deviates from a general rule, or a person or thing that is excluded from a rule or standard. The term is used across many contexts to indicate a departure from what is typical or expected, or to denote an exemption. In everyday language, phrases such as "with the exception of" signal exclusion; in law and policy, an exception is a provision that prevents a rule from applying to certain cases.

In logic and mathematics, an exception is a counterexample that disproves a universal claim or a special case not covered by a general statement. In statistics or everyday reasoning, exceptions illustrate the limits of a rule.

In computer science, an exception is an abnormal condition that interrupts the normal flow of a program’s execution. When such a condition is detected, a program may throw or raise an exception and transfer control to an exception handler, such as a try/catch block. Languages differ in whether exceptions are checked or unchecked, and in how they propagate and are recovered.

In summary, an exception marks a deviation or exemption from rules, norms, or expected behavior, and the concept plays a role in law, logic, mathematics, and software design, among other areas.