Self-descriptiveness is one of the principles for designing user-friendly interactive systems (interaction principles) from the DIN EN ISO 9241-110 standard.
An object or interface is self-descriptive if the users can recognize what they can do with it and how they must do it. At any point in time, it must be clear what is happening and how to interact. The ultimate goal is for a product to be self-descriptive without instructions or written directions. Only if this is not possible, help and feedback are necessary.