fasten

When you fasten a belt, a coat, a bag, etc., you join the two sides of it so it is closed.

Example: Please remain seated with your seat belts fastened.

If you fasten one thing to another, you attach them.

Example: The blackboard had been fastened to the front wall for years.

If you fasten your eyes or gaze on something, you look at it carefully without looking away.

Example: The boy's eyes were fastened on the TV.

If something won't fasten, its buttons or hooks won't join.

Example: The shirt was so small that the buttons wouldn't fasten.