Bedlam (noun)

1. A state of wild confusion or uproar; chaos.
2. A place, such as an institution for the mentally ill, where conditions are chaotic and disturbing.

Origin:

Bedlam, from the middle english word bedlem, meaning "madman" or "lunatic", which was derived from the name of the bethlehem hospital in london, which was known for its treatment of the mentally ill.

Examples:

1. The store was in bedlam as the sale started.
2. The party was bedlam, with people shouting and dancing everywhere.
3. The streets were in bedlam after the game ended.
4. The hospital was a bedlam, with patients screaming and running around.
5. The classroom was a bedlam, with students talking and not paying attention to the teacher.