Video is a technology. It records moving images onto some medium. The recorder may be a separate machine such as a videocassette recorder (also called a VCR) or built into something else such as a video camera.
A popular 20th century videotape format was VHS. It was used by many people to record television programmes onto cassettes. This is usually an analog format. In the 21st century digital recording is used more often than analog recording.
By extension, a video clip is a short movie. A music video usually stars someone who recorded an (audio) album. One purpose is to promote the album.