- Jetsam – Cargo which is thrown off a sinking ship.
- Judex est lex loquens – A judge is the law speaking.
- Judex non potest esse testis in propira causa – A judge cannot be witness in his own cause.
- Judex non potest injuriam sibi datam punire – A judge cannon punish a wrong done to himself.
- Judiciis posterioribus fides est adhibenda – Faith must be given to later decisions.
- Judicis est judicare secundum allegata et probata – It is the duty of a judge to decide according to the allegations and the proofs.
- Judicium non debet esse illusorium, suum effectum habere debet – A judgment ought not to be illusory; it ought to have its proper effect.
- Juduces non tenentur exprimere causam sententiae suae – Judges are not bound to explain the reason of their judgment.
- Jurat – Words at the end of an affidavit, showing the details of when and by whom it was sworn.
- Jura naturae sunt immutabilia – The laws of nature are immutable.
- Jus – A right that is recognised in law.
- Jus cogens – Fundamental principles of International Law.
- Jus naturale – Natural law.
- Jus in personam – Right against a specific person.
- Jus in rem – Right against the world at large.
- Jus non scriptum – Unwritten law; Customary Law.
- Jus scriptum – Written Law.
- Justitia est duplec; severe puniens et vere praeveniens – Justice is two-fold; severely punishing and in reality prohibiting (offences).
