friction

Friction is when two things rub against each other and don't slide easily.

When we talk about friction, we usually mean it in terms of movement or action. For example, imagine trying to open a door that's been left unlocked for too long - the lock gets stuck because of all the tiny movements back and forth between the door handle and the catch. That's an example of friction slowing things down. In everyday life, friction can be seen when you try to push or pull something heavy - it doesn't move smoothly until some force is applied to overcome that resistance.