The term 'storyboard' most commonly refers to a visual planning tool used in filmmaking, animation, advertising, and interactive media design. While there isn't one single, universally standardized file extension named '.storyboard' recognized across all professional software, this extension is often used by specialized storyboard creation applications to save their project files. These files typically contain a sequence of images or sketches representing the shots planned for a sequence, along with accompanying notes, dialogue, camera directions, and timing information. They are essentially structured data files that map out the narrative flow visually, frame by frame. The internal structure of such a file can vary significantly depending on the software used to create it—it might be an XML-based structure, a proprietary binary format, or even a collection of linked image files (like JPG or PNG) within a container. The primary purpose is to facilitate pre-production planning, communication between the director and the crew, and visualization of the final product before actual filming or animation begins.