Final answer:
A screenshot is an image captured of the whole screen, an active window, or a selected area on a computer or mobile device, typically used for sharing or documentation purposes.
Step-by-step explanation:
A screenshot is an image captured of the entire computer screen, an active window, or a selected portion of the screen. This digital image can be used for various purposes, such as saving or sharing a particular scene displayed on the screen. Screenshots are particularly helpful in demonstrating how software operates, documenting error messages, or capturing online content for personal reference. On most devices, taking a screenshot involves pressing a specific combination of keyboard buttons or using a designated software tool.