A screenshot, screen capture, or screen dump is an image taken by the computer to record the visible items displayed on the monitor or another visual output device. Usually this is a digital image taken by the host operating system or software running on the computer device, but it can also be a capture made by a camera or a device intercepting the video output of the computer.
Screenshots, screen dumps, or screen captures can be used to demonstrate a program, a particular problem a user might be having or generally when computer output needs to be shown to others or archived, or to simply show off what you do on your computer to others.
All three terms are often used interchangeably; however, some people distinguish between them as follows:
Screenshot Outputting the entire screen in a common bitmap image format such as BMP, PNG, or JPEG. Screen dump
The display system dumps what it is using internally upon request, such as XWD X Window Dump image data in the case of X11 or PNG in the case of Mac OS X. Screen capture (screencaps)
Capturing the screen over an extended period of time to form a video file