A fixation is an intense, often unhealthy focus on something that's hard to break away from. When you have a fixation on a video game, you can't stop thinking about it, even during dinner or while trying to do homework. When someone develops a fixation on a mistake they made, they replay it over and over in their mind instead of moving forward.

Fixations differ from ordinary interests or hobbies. Having a strong interest in dinosaurs means you enjoy learning about them. Having a fixation on dinosaurs means you struggle to think or talk about anything else, even when it's time to focus on other things. The word carries a sense of being stuck, like your attention is locked in place.

In psychology, fixations can prevent people from growing or adapting. A person with a fixation on being perfect might avoid trying new things for fear of making mistakes. Someone with a fixation on a past friendship might struggle to make new friends.

The word can also describe physical attachment. Dentists use the term fixation to describe how braces hold teeth in position, and surgeons might use metal plates for bone fixation after a fracture. But the mental meaning is more common: that feeling of being unable to let something go, even when you know you should.