PWA (progressive web app)
A website that behaves like an app: it can be installed to the home screen and can work offline.
Glossary · Apps & products
A PWA (progressive web app) is a website extended with a few browser technologies. It opens from a link like any website, but it can be added to the home screen, can keep part of its content for use without a connection and, if the user allows it, can send notifications.
The advantage is that no app store is needed: there is no review, updates reach everyone at once, and the code is the same for every device.
The drawbacks depend on the platform. Not every device feature is reachable from a browser, and iOS supports some capabilities more narrowly than Android. People also look for apps in the stores, where a PWA is usually absent.