flopover

From flop +‎ over.

• IPA^(key): /ˈflɒpəʊvə(ɹ)/

• Audio (Southern England):

  (file)

flopover (countable and uncountable, plural flopovers)

1. (television) A form of television signal distortion where the displayed image appears to scroll vertically rather than remaining still.
   • 1956, LIFE, volume 41, number 11, page 41:

     Now you have mirror-clear TV without picture flopover, jitter, tear!