Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definition and is usually used to refer to an invariant object under some transformations, including translation, reflection, rotation, or scaling. Although these two meanings of "symmetry" can sometimes be told apart, they are intricately related. Mathematical symmetry may be observed concerning the passage of time, as a spatial relationship, through geometric transformations, through other kinds of functional transformations, and as an aspect of abstract objects, including theoretic models, language, and music.