Definition: virtual hard drive

(1) A storage drive simulated in memory. See RAM disk.

(2) A virtual hard drive (VHD) is a storage format that contains all the structural elements of a hard drive or solid state drive (SSD). It is the storage architecture of a virtual machine. A fixed-size VHD takes up all the allotted space initially reserved, whereas a dynamically expanding VHD uses storage as it fills up to its assigned limit.

Create an Encrypted Drive
Although virtual machines are used to isolate different operating systems or applications in the same machine, a VHD can also be created as an encrypted storage drive that is separate from everything else stored in the computer. See virtual machine.