I just want to know the difference between "Unmounting" and "Detaching" in AWS EBS.
Unmount is an operation you perform at the operating system level. It would make the EBS volume unavailable to any software running on the instance, but from a "hardware" level the volume would still be attached to the EC2 instance.
Detach would completely disconnect the volume from the EC2 instance, and make it available to attach to a different instance.