An amercement is a financial penalty in English law, common during the Middle Ages, imposed either by the court or by peers. While it is often synonymous with a fine, it differs in that a fine is a fixed sum prescribed by statute and was often voluntary, while an amercement is arbitrary. They were commonly used as a punishment for minor offences, as an alternative to imprisonment.
Referred to in Frantz v. U.S. Powerlifting Federation 836 F.2d 1063 (7th Cir. 1987). In a discussion about the imposition of FRCP Rule 11 sanctions on a plaintiff's attorney, the decision says, "The complaint in this case was frivolous, which calls at a minimum for censure of Victor D. Quilici, the plaintiffs' lawyer. Whether it calls for amercement - and, if so, whether Cotter or the Treasury is the appropriate beneficiary - is something the district court should consider as an initial matter."