A storyboard is a technique for illustrating an interaction between a person and a product (or multiple people and multiple products) in narrative format, which includes a series of drawings, sketches, or pictures and sometimes words that tell a story.

Case studies on how storyboarding is used at leading companies world wideStoryboard That
Storyboards Help Visualize UX IdeasNielsen Norman GroupJuly 15th, 2018
The 8 Steps To Creating A Great StoryboardFast CompanyDecember 21st, 2013
Storyboarding in the Software Design ProcessUX MagazineFebruary 8th, 2013