Camera window
An invisible rectangle in the middle of the screen where the player moves freely — the camera only follows once the character pushes against its edge.
A camera locked rigidly to the player jerks with every step and hop, and quickly becomes tiring to watch. With a window, the view stays put while the character moves within the frame and only scrolls when it shoves against a border. There are endless variations: Super Mario Bros. (1985) scrolled forward and never back, Super Mario World only adjusted vertically once Mario had landed on a platform, and many games shift the window in the direction of travel so you see more of what is coming.
Itay Keren's "Scroll Back" talk at GDC 2015 catalogued dozens of these techniques and became the standard reference. Don't confuse it with an analogue-stick dead zone: both ignore small movements, but one concerns what the player does and the other what the player sees.