## coordinate system

(

*Also called*reference frame.) Any scheme for the unique identification of each point of a given continuum.These may be points in space (Eulerian coordinates) or parcels of a moving fluid (Lagrangian coordinates). Newton's laws of motion do take different forms in different systems (

*see*inertial coordinate system, relative coordinate system). The geometry of the system is a matter of convenience determined by the boundaries of the continuum or by other considerations (*see*Cartesian coordinates, curvilinear coordinates).