collision

A collision is when two or more things crash into each other.

Imagine you're driving your car and suddenly someone runs into it from behind. That's a collision. Or think about a game of pool: when one ball hits another, that's also a collision. In science class, they might talk about collisions between atoms or particles in space. The idea is always the same – two things bumping into each other with force.

In everyday language, people usually use "collision" to describe something unexpected happening because two objects are moving towards each other and can't avoid hitting. It's often used when talking about cars, sports, or even accidents on a skateboard or bike.