The acronym REST stands for Representational State Transfer, a software architectural style used in web APIs. RESTful APIs adhere to a set of constraints and principles, including stateless communication and the use of standard HTTP methods like GET, POST, PUT, and DELETE. This approach allows for easy integration and interaction with web services, promoting scalability and efficient data exchange. REST has gained popularity due to its simplicity, allowing developers to create APIs that are easy to consume and maintain.