App states or Application states

1. Non-running - The app is not running. 
2. Inactive - The app is running in the foreground, but not receiving events. An iOS app can be placed into an inactive state, for example, when a call or SMS message is received. 
3. Active - The app is running in the foreground, and receiving events. 
4. Background - The app is running in the background, and executing code. 
5. Suspended - The app is in the background, but no code is being executed.