Discoverability, in design, refers to users' ability to find key information, applications or services. Discoverability allows users to locate something they need in order to complete a certain task. Discoverability is most often used to refer to what is noticeable to users on a particular Web page. Discoverability is a challenge for designers because it can be difficult to prioritize discoverability, as not everything can be be equally visible.
Techopedia explains Discoverability
How to provide users with the right content at the right time is a major challenge for any website as it requires designers and developers to consider how users will experience a given design.
Discoverability can be achieved in a number of ways. These include:
Size: Any element of a page that takes up more pixels is more likely to be noticed by users.
Order: The order in which items on a page are placed can affect discoverability. Heat mapping of a given page can help give designers a sense of what areas grab users' attention.
Design Elements: Color, font, shape, shadow and other design elements can all help to direct users' attention to specific areas of a page.
Flow: Discoverability should aim to highlight the things a user needs most at any given time. For example, on a shopping website, the "Checkout" button should be easily discovered by users who have selected items for purchase.
Consistency: By employing a similar style and logic consistently, designers can make life easier for users, who will be able to learn and become accustomed to the system.
This definition was written in the context of Design