useability - able or fit to be used; judged by the useability principles of efficiency accessibility(?), effectiveness, safety, utility and learnability

useability principles - principles used to improve the user experience, including

• accessibility: ability to be used by many different people, even people with disabilities
• effectiveness: ability of users to use the system to do the work they need to do, includes reliability
• safety: ability for users to make errors and recover from the mistake
• utility: ability of the system to provide all the functionality that users need
• learnability: how easy a system is to learn

user experience - those aspects that affect how an end user interacts with digital systems such as visual, interface and navigation design, user needs, and functional and content requirements; this is determined by improving the solution’s useability based on the useability principles of accessibility, effectiveness, safety, utility and learnability (VCAA, 2014)