Definition - What does Root Partition mean?
A root partition is a type of partition within the Windows Hyper-V virtualization environment that is responsible for running the hypervisor. The root partition enables the execution of primary hypervisor software and manages the machine level operations of the hypervisor and created virtual machines.
Techopedia explains Root Partition
The root partition is generally considered the parent partition; however, it is actually a logically distributed partition for hypervisor-specific operations.