Definition - What does Frame Grabber mean?
A frame grabber is a hardware device used to convert a video frame to a single, still bitmapped image. Frame grabbers were initially standalone cards that attached to a computer port, but now they are available as part of video capture boards or display adapters in most computers.
Techopedia explains Frame Grabber
Individual still frames are captured through a frame grabber from an analog or digital video stream. Due to its image/video processing technique, a frame grabber is used as part of computer vision systems where processing, storing and other tasks are done in digital form. Early manufactured frame grabbers had only enough memory to store one digital image, but with more advanced current technology, a user can store, transmit and display multiple images at the same time.