Ius - N

Ius naturae. Literally, “the law of nature”. In Roman law, a near synonym for ius naturale—a law that is supported by natural reason, and so a law that is, or ought to be, respected by the laws of all nations. Thus, the ius naturae was said to support the ius gentium in its universal sense. However, even this relationship is not always congruent: famously, in the introduction to Justinian’s Institutes, slavery is forbidden by nature but allowed by the ius gentium. Even so, there was the general sense, seized on increasingly from Roman writings throughout the Renaissance and early modern age, that civil law was to reflect the obligations of natural law, especially when natural law required freedom.
Ius naturale. The natural law, or law of nature; law or legal principles, supposed to be discoverable by the light of nature or abstract reasoning, or to be taught by nature to all nations and men alike; or law supposed to govern men and peoples in a state of nature i.e., in advance of organized governments or enacted laws. This conceit originated with the philosophical jurists of Rome, and was gradually extended until the phrase came to denote a supposed basis or substratum common to all systems of positive law, and hence to be found, in greater or less purity, in the laws of all nations. And, conversely, they held that if any rule or principle of law was observed in common by all peoples with whose systems they were acquainted, it must be a part of the ius naturale, or derived from it. Thus the phrases "ius naturale" and "ius gentium" came to be used interchangeably.

As the Roman jurist Ulpian said, “...that which nature taught all animals.” For most writings of classical Roman law, synonymous with ius naturae. From the writings of Paul, however, the term ius naturale acquired the sense of an ideal of law, quod semper est bonum et aequum— those actions that are always fair and just. This sense is followed in the Thomist conceptions of natural law, or lex naturalis.

ius naturale est quod apud homines eandem habet potentiam. "Natural right is that with the same force among all mankind". 7 Coke, 12.

Ius navigandi. The right of navigating or navigation; the right of commerce by ships or by sea. Locc. de Jure Mar. lib. 1, c. 3.
Ius necis. In Roman law, the right of death, or of putting to death. A right a father anciently had over his children.
Jus non habenti tute non paretur. "One who has no right cannot be safely obeyed". Hob. 146.
Jus non patitur ut Idem bis solvatur. "Law does not suffer that the same thing be twice paid".
Ius non scriptum. The unwritten law. 1 Bl. Comm. 64. .
Ius offerendi. In Roman law, the right of subrogation, that is, the right of succeeding to the lieu and priority of an elder creditor on tendering or paying into court the amount due to him. See Mackeld. Rom. Law, § 355.