A more thorough explanation:

Natural law

1. The physical laws of nature.
2. A philosophical theory claiming to derive moral and legal principles from a set of universal truths about people and justice.

See Positive law and Moral law.

Natural law can refer to the physical laws that govern the natural world, such as the laws of gravity or thermodynamics. It can also refer to a philosophical theory that suggests there are universal truths about what is right and wrong, and that these truths can be used to create moral and legal principles. For example, the idea that all humans have inherent dignity and worth could be used to argue that certain actions, such as slavery or genocide, are always wrong, regardless of the cultural or historical context. This theory of natural law has been influential in many areas of philosophy and law throughout history.

• The law of gravity, which states that objects are attracted to each other with a force proportional to their masses and inversely proportional to the distance between them.
• The idea that all humans have a right to life, liberty, and the pursuit of happiness, which is enshrined in the United States Declaration of Independence and has been used to argue for various human rights throughout history.

These examples illustrate the two different meanings of natural law. The law of gravity is an example of a physical law that governs the behavior of the natural world. The idea of inherent human rights is an example of a moral principle that some philosophers have argued is a universal truth that can be used to create legal principles.