Physics is a discipline of science.
Physics ( from the Ancient Greek φύσις physis meaning `` nature '' ) is the fundamental branch of science that developed out of the study of nature and philosophy known , until around the end of the 19th century , as `` natural philosophy '' . Physics ( from [ φυσική , phusikḗ ( epistḗmē ) , knowledge of nature ] , from φύσις phúsis `` nature '' ) is the natural science that involves the study of matter and its motion and behavior through space and time , along with related concepts such as energy and force . One of the most fundamental scientific disciplines , the main goal of physics is to understand how the universe behaves .