What is the difference between hmc and hac?

Hybris Management Console (HMC):

Hybris Management Console (HMC) is the administration tool for Hybris Commerce. Using the HMC, you can manage SAP Hybris Commerce business objects such as products, customer data, and orders.

Hybris Administration Console (HAC):

The Hybris Administration Console is an administration Web page provided by the hac extension.

It provides functionality for administration, monitoring, and configuration of SAP Hybris Commerce.

In addition, it links to the documentation resources for SAP Hybris Commerce.