Oscilloscope designed for television that looks at luminance and other parts of the composite video signal. The video waveform is made up of several parts (sync, blanking, video, etc.) that are all required to make up a TV picture that can be accurately displayed.
https://www.nfsa.gov.au/sites/default/files/uploads/2010/09/06/wave2.gif
A Vectorscope is an oscilloscope designed for television that looks at chrominance portion of a video signal.