A graphic presenting a design direction.
A moodboard shows the main design direction that a user interface could look like.
Multiple kinds of moodboards
There are multiple kinds of moodboards. The most common one shows the color scheme of the product, software or service. It contains images and colored shapes most of the time.
Another category of moodboards are moodboards that contain other user interfaces as a inspiration for the UI Elements and show what their visual appearance look like and if they e.g. have shadows or not.
A Designbeam combines a moodboard with a persona and a use context visualisation.