What is defined as the physical computer on which ESXi is installed?

The term that describes the physical computer on which ESXi is installed is "host." In the context of VMware vSphere, the host serves as the underlying hardware that runs the ESXi hypervisor. This hypervisor enables virtualization by allowing multiple virtual machines (VMs) to operate concurrently on the same physical server, effectively utilizing resources and providing isolation between different operating systems.

Understanding this concept is crucial as it forms the foundation of VMware's virtualization framework. The host is responsible for managing the physical resources, such as CPU, memory, storage, and network connections, which are shared among the virtual machines it supports.

In contrast, the other terms relate to different components of the VMware ecosystem. A data center is a collection of physical resources that can include multiple hosts, while a cluster refers to a group of hosts that work together to provide high availability and load balancing for VMs. A datastore is a storage unit used to hold VM files and virtual disk images, but it does not represent the physical hardware itself.