Availability

Availability is in the context of product design, the probability that a product, when used under given conditions, will perform satisfactorily when called upon.

Definitions

According to Juran's Quality Handbook by Defeo (7th edition),

Availability. In the context of product design, the probability that a product, when used under given conditions, will perform satisfactorily when called upon.

According to the ITIL Foundation 4e by Axelos,

Availability. The ability of an IT service or other configuration item to perform its agreed function when required.