As a domain expert in database management, I can explain that NoSQL stands for "not only SQL" and it refers to a variety of database systems that do not use the traditional structured query language (SQL) for data management. NoSQL databases are known for their flexibility, scalability, and ability to handle unstructured or semi-structured data, which makes them particularly useful for big data applications and real-time web applications that require high performance and the ability to handle large volumes of data. NoSQL databases often use different data models, such as key-value, document, wide-column, or graph databases, each optimized for different types of data and access patterns. They are designed to handle vast amounts of data across multiple servers or locations, which is a common requirement for modern web applications that need to scale horizontally. read more >>

A NoSQL (originally referring to "non SQL" or "non relational") database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. ... NoSQL databases are increasingly used in big data and real-time web applications.read more >>