<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> A scientific theory is an explanation of some aspect of the natural world that can be repeatedly tested, in accordance with the scientific method, by using a predefined protocol of observations and experiments . Established scientific theories have withstood rigorous scrutiny and are a comprehensive form of scientific knowledge . </P> <P> It is important to note that the definition of a "scientific theory" (often contracted to "theory" for the sake of brevity, including in this page) as used in the disciplines of science is significantly different from the common vernacular usage of the word "theory". In everyday non-scientific speech, "theory" can imply that something is an unsubstantiated and speculative guess, conjecture, idea, or, hypothesis; such a usage is the opposite of the word "theory" in science . These different usages are comparable to the differing, and often opposing, usages of the term "prediction" in science versus "prediction" in vernacular speech, denoting a mere hope . </P>

Something that explains a relationship in the natural world is called