A NoSQL database is a type of database that does not use tables, rows, and columns to organize data. Instead, it uses keys and values to store data in a flexible and scalable way. A key is a unique identifier for a piece of data, and a value is the data itself. For example:

{ “name”: “Alice”, “age”: 25, “city”: “New York” }

In this example, name, age, and city are keys, and Alice, 25, and New York are values.

References: CompTIA IT Fundamentals+ Study Guide: Exam FC0-U61, Second Edition, Chapter 5: Database Fundamentals, page 196.