Bill comes from the Latin word bulla, a seal used on documents during the Middle Ages. Gradually the word came to be used for the paper itself. In England and France, the similar words bill and billet meant less formal writing as well. In English, the term refers to many written or printed papers. These are bills of attainder, exchange, health, rights, and sale. Posters and theater programs are called bills. In the United States, a bill also means paper money. Important forms of bills include: