As a generalization: Video, going back to before the digital era, refers to images recorded on magnetic videotapes, such as VHS or Betamax. This is in contrast with film, which is images recorded using light sensitive silver halide crystals. Video tapes are viewed by scanning the magnetic strips and displaying on a monitor with scan lines. Films are viewed by shining a light through the developed film and displaying the whole image on a reflective screen.
Not quite. Video is generally an electronic medium for moving pictures and can be sent over cables or radio waves from the camera to the TV, without touching a tape. A video signal can be recorded on a tape, but isn't necessarily.
Yes, you are right. Looks like you squeezed in your comment before I was able to put the "as a generalization" disclaimer on it! :)
I was thinking more of the situation where some people might be confused with the Zapruder recording, that it could be on videotape instead of film, which is why I didn't try to cover all the corner cases.