natural sciences

n. exact sciences, science dealing with observable natural phenomena (includes biology, physics, chemistry, etc.)

n. science that studies nature and the physical world

In science, the term natural science refers to a rational approach to the study of the universe, which is understood as obeying rules or laws of natural origin. The term natural science is also used to distinguish those fields that use the scientific method to study nature from the social sciences, which use the scientific method to study human behavior and society, and from the formal sciences, such as mathematics and logic, which use a different methodology.
See more at Wikipedia.org...