Structured data refers to any data that resides in a fixed field within a record or file, including data contained in relational databases and spreadsheets. Phone numbers, represented in a consistent format, are an example of structured data, as they can be easily organized in a database or spreadsheet. This contrasts with unstructured data like video recordings, social media posts, and photographs, which do not follow a predictable format or structure.
Reference: The classification of data types is a standard topic in IT education, covered under the CompTIA IT Fundamentals.