Let’s learn from the scracth. “Fade” literally defined as gradually grow faint and disappear. It also a process to become disappear or less bright.
Fade refers to a visual effect used to indicate a change in place and time. Tehcnically it involves a gradual brightening as a shot opens or a gradual darkening as the shot goes black or to another color. Sound also fades in and out to convey the change.