Line Skipping
Reading only a fraction of a sensor's rows to produce a lower-resolution image quickly, discarding the rest.
In depth
Skipping is fast and cheap but throws away information that could have been averaged, so it delivers neither the noise benefit of binning nor the detail of full readout — and because it samples a subset of the grid, it makes aliasing and moiré markedly worse. It is why early hybrid cameras produced such poor video from excellent sensors.
Examples in practice
Line-skipped 1080p footage from an early DSLR shows severe aliasing on brickwork that the stills never displayed.