From Citizendium, the Citizens' Compendium
- Universe : The summation of all particles and energy that exist and the space-time in which all events occur.
- World : That part of the universe from which humanity has perceived signals; often used synonymously for Earth.
- Natural science : The study of nature using the scientific method.
- Physics : The study of forces and energies in space and time.
- Chemistry : The science of matter, or of the electrical or electrostatical interactions of matter.
- Biology : The science of life — of complex, self-organizing, information-processing systems living in the past, present or future.
- Earth science : The study of the components and processes of the planet Earth.
- Culture : Please do not use this term in your topic list, because there is no single article for it. Please substitute a more precise term. See Culture (disambiguation) for a list of available, more precise, topics. Please add a new usage if needed.
- Religion : Belief in, and systems of, worshipful dedication to a superhuman power or belief in the ultimate nature of existence.
- Evolution : A change over time in the proportions of individual organisms differing genetically.
- Human evolution : The study of the physical and behavioral genetic adaptations of the species belonging to the subfamily hominidae.
- Natural number : An element of 1, 2, 3, 4, ..., often also including 0.
- Natural history : The study of natural objects or organisms often relating to biology.
- Naturalism : A concept with the view that ultimately nothing resists explanation by the methods characteristic of the natural sciences.