Definition - What does Ubuntu Cloud mean?
Ubuntu cloud is an online platform that is designed to allow users to create their own private or public cloud infrastructure. Ubuntu cloud users can select the services they wish to provide to their users as well as use the public cloud when more processing power is needed. The Ubuntu cloud is accessible through the Ubuntu operating system, specifically as an extension of the Ubuntu Server Edition.
Techopedia explains Ubuntu Cloud
Ubuntu cloud allows a user to designate node servers using a controller computer. When the number of services being accessed on the cloud exceeds the capacity of the nodes, the excess can be passed off to the public cloud. The Ubuntu cloud is intended to reduce the costs of implementing a private cloud while still maintaining compatibility with the public cloud.