A volume or set of volumes that is a record of the status of cases or statutes.
A citator is a guide published primarily for use by judges and lawyers when they are in the process of preparing such papers as judicial decisions, briefs, or memoranda of law. Its purpose is to provide a judicial history of cases and statutes as well as to make a note of new cases. A citator indicates whether or not the law in a particular case has been followed, modified, or overruled in subsequent cases.
A citator is usually organized into columns of citations. Various abbreviations designate such things as whether a case has been over-ruled, superseded, or cited in the dissenting opinion of a later case.
The most well-known and commonly used citator is shepard's citations. The process of consulting this book or any other citator is known as shepardizing a case.