A Progressive Web App is an application that has been built using a set of web development techniques and technologies that help enable a web site to be progressively installed and act like a mobile application as the user becomes increasingly engaged with the experience. A Progressive Web App should work offline and be launchable as a standalone experience, and may also offer enhanced experiences such as Push Notifications, integrations with the system's "Share" experience and other device capabilities.
A core tenant of a Progressive Web Apps is Progressive Enhancement which enables a developer to build an experience that works across as many platforms as possible and be enhanced on platforms where technologies (most significantly, perhaps, Service Worker) exist.
