The PUT method is one of the HTTP (Hypertext Transfer Protocol) methods, which is used to update or replace an existing resource on the server. This method is typically used to update contents or properties of a particular resource which were previously created using a POST or PUT method. In other words, the PUT method requests the server to update or replace the contents of an existing resource with the new content provided in the request. The PUT method is an idempotent operation, meaning it can be executed multiple times with the same data without causing any negative side effects.