A false boast by someone intended to increase his standing at the expense of another. This formed the basis of an ancient legal petition called “jactitation of marriage” in which a person could be ordered by the courts to cease claims of being married to a certain person when, in fact, they were not married. The tort of slander of title (which see) is a form of jactitation.

J. D.

Abbreviation for “juris doctor” or “doctor of jurisprudence” and the formal name given to the university law degree in the United States. It is a prerequisite to most bar admission exams.

Joint and several liability

A legal term allowing each party having liability to be sued for the entire amount of damages done by all the parties.

Joint custody

A child custody decision in which both parents share joint legal custody and joint physical custody. This is not common and many professionals have taken to referring to “joint legal custody but sole maternal physical custody” as “joint custody”.

Joint tenancy

When two or more persons are equally owners of some property. The unique aspect of joint tenancy is that as the joint tenancy owners die, their shares accrue to the surviving owner(s) so that, eventually, the entire share is held by one person. A valid joint tenancy is said to require the “four unities”: unity of interest (each joint tenant must have an equal interest including equality of duration and extent), unity of title (the interests must arise from the same document), unity of possession (each joint tenant must have an equal right to occupy the entire property) and unity of time: the interests of the joint tenants must arise at the same time.

Judicial review

A process whereby a court of law is asked to rule on the appropriateness of an administrative agency or tribunal’s decision. Judicial review is a fundamental principle of administrative law. A distinctive feature of judicial review is that the “appeal” is not usually limited to errors in law but may be based on alleged errors on the part of the administrative agency on findings of fact.


Latin, from Roman law: by right, under legal authority or by the authority of the law. A variation, “juris” means “of right” or “of the law.” See jurisprudence below which means “science of the law.”


A court’s authority to preside over a situation, usually acquired in one of three ways: over acts committed in a defined territory (e.g. the jurisdiction of the Supreme Court of Illinois is limited to acts committed or originating in Illinois); over certain types of cases (the jurisdiction of a bankruptcy court is limited to bankruptcy cases); or over certain persons (a military court has jurisdiction limited to actions of enlisted personnel).


Technically, jurisprudence means the “science of law”. Statutes articulate the rules of law, with only rare reference to actual situations. The application of these statutes to actual cases and facts is left to judges who consider not only the statute but also other legal rules which might be relevant to arrive at a judicial decision; hence, the “science”. Thus, “jurisprudence” has come to refer to case law, or the legal decisions which have developed and which accompany statutes in applying the law against situations of fact.


A group of citizens randomly selected from the general population and brought together to assist justice by deciding which version, in their opinion, constitutes “the truth”, given different evidence by opposing parties.


Latin: word which, in Roman law, meant the law or a right. Also spelt “ius” in some English translations.

Jus spatiandi et manendi

Latin: referring to a legal right of way, and to enjoyment, granted to the public but only for the purposes of recreation or education, such as upon parks or public squares. Some courts have said that a jus spatiandi is a special type of easement.

Justice Fairness

A state of affairs in which conduct or action is both fair and right, given the circumstances. In law, the paramount obligation to ensure that all persons are treated fairly. Litigants “seek justice” by asking for compensation for wrongs committed against them that will right the inequity such that the balance of “good” or “virtue” over “wrong” or “evil” has been corrected.