A stack is a collection of AWS resources that you can manage as a single unit. In other words, you cancreate, update, or delete a collection of resources by creating, updating, or deleting stacks. All theresources in a stack are defined by the stack's AWS CloudFormation template. A stack, for instance,can include all the resources required to run a web application, such as a web server, a database, andnetworking rules. If you no longer require that web application, you can simply delete the stack, andall of its related resources are deleted.