CRUD is an acronym for the four basic operations used in data processing and database management. CRUD stands for:

1. Create: Adding new data or records to a database or system.
2. Read: Retrieving or reading data or records from a database or system.
3. Update: Modifying or editing existing data or records in a database or system.
4. Delete: Removing data or records from a database or system.

These four operations are fundamental for managing persistent data in applications, whether in relational databases, NoSQL databases, or other data storage systems. CRUD operations form the foundation of many software applications, especially those that heavily utilize databases, such as web applications, business applications, and many other types of software systems.

In practice, CRUD operations are often implemented using specific commands or methods of a programming language or a database system. For example, SQL commands such as INSERT, SELECT, UPDATE, and DELETE in a relational database.