Interlaced Video is a way of displaying pictures on a screen by showing only half the image at a time—first the odd lines, then the even lines.
This method was common in old TVs and broadcast signals (marked with an “i” like 1080i).
Modern TVs use progressive scan (marked with a “p” like 1080p), which shows the full image at once, making motion smoother and sharper.
See also: Progressive Scan, Refresh Rate, Resolution