What Does External Cloud Mean?
An external cloud is a cloud solution that exists outside of an organization's physical boundaries. It can be private, public or community-based, as long as it is not located on an organization's property.
An external cloud is similar to a public cloud, but they differ in implementation.
Techopedia Explains External Cloud
An external cloud involves sourcing any available cloud solution to be used in connection with internal cloud or IT infrastructure resources for virtually any business need. An external cloud can have various forms of delivery. In terms of a proprietary external cloud, an organization might install and host its physical servers at a cloud vendor co-location facility. The services delivered through this cloud solution will match that of a private cloud, but all the physical resources are external to the organization.
In a non-proprietary model, a cloud vendor might provide the entire cloud infrastructure and resources to selected organizations. Such cloud solutions are generally not marketed explicitly or to the general public.