Interlacing
Interlacing is an older way of building an image, where each frame consists of two half-images that alternately show the odd and even lines. It still appears in TV material and some cameras. In modern work you almost always want progressive footage, where each frame is complete.
If you spot jagged, comb-like edges on motion, you're looking at interlaced footage that hasn't been handled well. In DaVinci Resolve, Premiere Pro and Final Cut Pro you can fix this with de-interlacing, which merges the half-images into whole frames. If you work with modern, progressive footage (like 1080p), interlacing usually doesn't play a role. Tip: if you were handed old TV or archive material, check whether it's interlaced before you start editing.
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