Definition - What does Cloud Portability mean?
Cloud portability makes it possible to switch a cloud solution between different vendors and/or migrate it across internal cloud infrastructure.
Techopedia explains Cloud Portability
Cloud portability is applicable to all service models of cloud computing - SaaS, PaaS, IaaS and hybrid - regardless of whether they are public or private. However, most cloud portability scenarios occur in public-to-public or public-to-private cloud transfer.
Cloud portability depends on the level of interoperability a cloud service or vendor provides in their offerings. A cloud solution built on non-proprietary and open standards is most likely to be easily portable among any similar cloud vendors or architecture. OpenStack and CloudStack are among the initiatives that fosters cloud solutions, which are highly interoperable among supporting vendors.