ANR
Also called: App not responding
Application Not Responding: Android's dialog when an app freezes for about 5 seconds.
Definition
An ANR happens when the app's main thread is blocked. Testers report it like a crash, with steps and the 'ANR in' section from logcat.
In practice
Tapping Export on a large order history freezes the app, and Android asks 'App isn't responding. Close app?'