A website that can be installed on a phone's home screen and behaves like an app, without going through app stores.
PWA stands for progressive web app. It is a regular website with added capabilities that make it feel like an app: a home screen icon, full-screen launch, partial offline use and, on some devices, notifications. It updates instantly like any website, with no store review to wait for.
It is a great way to start: lower cost, one version for every device and instant deployment. But on some devices and features it is less capable than a native app, and it does not appear in app stores where some customers search. Practical tip: if customers visit occasionally, a PWA is often enough at first. If you need reliable notifications, deep device access or store presence, consider a native app. See mobile apps.