An Object Identifier (OID) is a unique identifier used to label objects in various fields, such as computer science, telecommunications, and healthcare. OIDs are structured as a series of numbers separated by dots, allowing for a hierarchical organization. They help ensure that each object, like a medical device or software component, can be distinctly recognized and referenced. OIDs are commonly used in protocols like SNMP (Simple Network Management Protocol) and standards such as X.500 for directory services. By providing a standardized way to identify objects, OIDs facilitate interoperability and data exchange across different systems and applications.