An Object Identifier (OID) is a unique string of numbers used to identify an object or entity in various systems, particularly in databases and networking. OIDs help ensure that each object can be distinctly recognized, preventing confusion or duplication. They are commonly used in protocols like SNMP (Simple Network Management Protocol) and in directory services like LDAP (Lightweight Directory Access Protocol). OIDs are structured hierarchically, often represented as a series of numbers separated by dots, such as 1.3.6.1.4.1. This structure allows for organized categorization and easy retrieval of information. Each number in the sequence corresponds to a specific category or subcategory, making it easier to manage complex data systems.