. . . "Physics (from the Ancient Greek \u03C6\u03CD\u03C3\u03B9\u03C2 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\". Today, physics is ultimately defined as the study of matter, energy and the relationships between them."@en .