What is defined as the ability to access data and applications whenever they are needed?

The term that refers to the ability to access data and applications whenever they are needed is "Cloud Availability." This concept is crucial in cloud computing as it ensures that resources are consistently accessible to users, promoting seamless operations without interruption. High availability is often achieved through techniques such as redundancy, failover systems, and effective load balancing, which allows users to retrieve their data and use applications without significant downtime.

While cloud accessibility also relates to the ease of obtaining data and applications, it focuses more on the ease of use for people with different abilities or the availability of data through various devices. Cloud security pertains to measures that protect data, applications, and services from unauthorized access and cyber threats, which is a different aspect altogether. Cloud scalability involves the capacity of a cloud system to grow and manage increased demand, which is important but does not directly address the immediate availability of resources. Therefore, the focus on "availability" is what distinguishes this term as the correct answer.