What is defined as "a concise statement about a fundamental relationship in nature"?

A "law" in scientific terms refers to a concise statement that describes a fundamental relationship or phenomenon observed in nature. Scientific laws are derived from consistent experimental observations and are universally applicable, often expressed mathematically. They describe what happens under certain conditions without delving into why it happens. For instance, Newton's Law of Universal Gravitation succinctly expresses the relationship between the masses of two objects and the gravitational force between them.

In contrast, a theory is a broader explanation that encompasses a range of hypotheses and is supported by a substantial body of evidence; it provides a framework for understanding phenomena but does not serve as a simple statement of relationship. A hypothesis is a specific, testable prediction that can be investigated through experimentation. Lastly, the term "principle" is often used similarly to "law," but can imply a more general understanding or foundational concept that guides scientific reasoning, yet is not strictly defined as a precise relationship.