Cloud storage refers to solutions where the physical storage is available as a service. This can be commercial providers like DropBox, or institutional solutions – or somewhere in between. Common to the solutions will be an app, or utilizing a standard protocol, for providing access to files that are not stored on your device, e.g. your laptop or phone. However, often the cloud storage solution will synchronize the files – or at least need to copy them on a case by case basis – to be able to provide access.