The term "hybrid cloud" in popular vocabulary represents a topology in which an organization's IT infrastructure is spread over public cloud(s) and on-premise data centers. An on-premise datacenter can include the enterprise's own data center or any colocation facility used by the enterprise. Hybrid has also lately been extended to include edge locations whether in a device or in a telecom provider's location. These variants are sometimes also referred to as "private cloud."
Although in a utopian world, the complete data center can be placed in the cloud, in reality, there are invariably some use cases that require workloads to be running on-premise. This is especially true of large enterprises that have considerable IT assets many of which need to continue to reside in the private cloud for various reasons.