A hive in the Windows registry is the name for an important part of the registry that contains registry keys, registry subkeys, and registry values.

All keys that are considered hives begin with "HKEY" and are located in the root, or at the top of the hierarchy in the registry. For this reason, they are sometimes also called root keys or core system hives.

To use a more general term, a hive is like a home directory in the registry. Everything in the registry is eventually contained in different hives.

In the Registry Editor, hives are the set of registry keys that appear as folders on the left side of the screen when all other keys are minimized.