Cumulative Layout Shift (CLS)
Cumulative Layout Shift (CLS) measures visual stability on a web page. Ideally the interface should be as visually stable as possible during loading.

Cumulative Layout Shift is part of the core web vitals as one of the three main metrics used to measure site speed. Learn more on how you can design for site speed.
Have a look at the factors that Impact LCP, FID/TBT, and CLS scores and research on the state of Core Web Vitals here.