Spring
A pull back toward a resting place that grows stronger the further something is pushed.
See it in Dither playground. Move the pointer through the dots, then raise Spring and watch them snap home.
In plain words
Stretch a spring and it pulls back. The further you stretch it, the harder it pulls. Let go and it rushes back, overshoots, and swings to and fro. Animation uses springs so things move with a lively bounce instead of a fixed timing. Damping decides how quickly the bouncing settles.