JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write. It uses a simple text format to represent structured data, making it ideal for transmitting information between a server and a web application. In JSON, data is organized in key-value pairs, similar to how objects are structured in JavaScript. This format supports various data types, including strings, numbers, arrays, and nested objects, allowing for complex data structures to be represented clearly and concisely.