Energy
In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton.
Engineering
Engineering is the creative application of science, mathematical methods, and empirical evidence to the innovation, design, construction, operation and maintenance of structures, machines, materials, devices, systems, processes, and organizations. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering.
Production Engineering
Production engineering is a combination of manufacturing technology, engineering sciences with management science. A production engineer typically has a wide knowledge of engineering practices and is aware of the management challenges related to production. The goal is to accomplish the production process in the smoothest, most-judicious and most-economic way.
Production
Part of the goods which are annually produced, and which are called wealth, is, strictly speaking, waste, because it consists of articles which ... either should not have been produced until other articles had already been produced in sufficient abundance, or should not have been produced at all. And some part of the population is employed in making goods which no man can make with happiness, or indeed without loss of self-respect, because he knows that they had much better not be made; and that his life is wasted in making them.
R. H. Tawney, The Acquisitive Society (1920), pp. 37–38.