In engineering, reliability, availability, maintainability and safety (RAMS)^[1][2] is used to characterize a product or system:

• Reliability: Ability to perform a specific function and may be given as design reliability or operational reliability
• Availability: Ability to keep a functioning state in the given environment
• Maintainability: Ability to be timely and easily maintained (including servicing, inspection and check, repair and/or modification)
• Safety: Ability not to harm people, the environment, or any assets during a whole life cycle.