Identifier systems are methods used to uniquely distinguish items, people, or concepts within a specific context. These systems help avoid confusion by assigning a unique code or label, such as a Social Security Number for individuals or a ISBN for books. This ensures that each entity can be easily referenced and retrieved without ambiguity. Common examples of identifier systems include barcodes used in retail, email addresses for online communication, and UUIDs (Universally Unique Identifiers) in software development. These systems enhance organization, improve data management, and facilitate efficient communication across various fields and industries.