Which term refers to how easy it is for a user to learn how to use a solution?

The term that refers to how easy it is for a user to learn how to use a solution is usability. Usability encompasses various dimensions of the user experience, one of which includes how quickly and effectively users can learn to interact with a system or product. It focuses on ensuring that the interface is intuitive and straightforward, enabling users to navigate and accomplish tasks with minimal effort.

Usability is critical in design as it directly impacts the user's ability to utilize a system efficiently and effectively from the moment they begin using it. This aspect involves not only the ease of learning but also how well users can remember usage after a period of not engaging with the product and how satisfaction is maintained throughout their interactions.

In contrast, accessibility relates more to how inclusive a solution is for users with disabilities, ergonomics focuses on comfortable use and the physical interaction with tools or systems, and user-friendliness is often considered a less formal synonym for usability but does not encapsulate all elements of user interaction and learning. Thus, usability is the most precise term for the context of learning how to use a solution.