NoSQL stands for "Not Only SQL" and refers to a type of database management system that is designed to handle large volumes of unstructured and semi-structured data. Unlike traditional SQL databases that use a tabular format with predefined schemas, NoSQL databases are schema-less and allow for flexible and dynamic data structures.
NoSQL databases are required because they can handle the large volumes and complex data types associated with Big Data. They are designed to scale horizontally by distributing data across many servers, making them well-suited for handling large and growing datasets. Additionally, NoSQL databases are often faster and more efficient than SQL databases for certain types of queries, such as those involving large amounts of data and complex data structures.