Astronomy (n): The scientific study of matter in outer space, especially the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial bodies and phenomena.

Biology (n): The science of life and of living organisms, including their structure, function, growth, origin, evolution, and distribution. It includes botany and zoology and all their subdivisions.

Chemistry (n): The science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems.

Earth Science (n): Any of several essentially geologic sciences that are concerned with the origin, structure, and physical phenomena of the earth.

Physics (n): The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics, and electromagnetism, as well as in modern extensions including atomic and nuclear physics, cryogenics, solid-state physics, particle physics, and plasma physics.