REST stands for Representational State Transfer, which is an architectural style for designing web services that adhere to certain principles. One of these principles is statelessness, which means that each request from a client to a server must contain all the information necessary to understand the request, and that no session state is maintained on the server side. Another principle is uniform interface, which means that clients and servers communicate using a standardized protocol, such as HTTP, and use its features, such as headers and status codes, to exchange information about the resources and their representations.