Abandoned Calls: Calls disconnected by customers even before your agents could attend are called abandoned calls. This can happen while the customers wait in the call queue or listen to welcome greetings. Check out this article to understand the importance of tracking abandoned calls.

Missed Call: If you select Hangup as the fallback action for a call handling rule in any of your call workflows and if the hangup action is executed, the call is considered a Missed Call.

For example, consider that your call queue setup has hangup as the fallback action to take if your agents are busy. In this case, if customers call and all your agents are busy, the call hangs up and is marked as a missed call.
You can view the list of the abandoned and missed calls in the Call Metrics section by filtering the call type as abandoned or missed. Additionally, for abandoned calls, you can also check the abandonment reason.