The term 'Unit of Work or Energy' can be summarized by two crossword solutions: ERG (3 letters) and JOULE (5 letters). An ERG is a unit of energy or work equal to the work done by a force of one dyne acting over a distance of one centimeter. A JOULE is a derived unit of energy, work, or amount of heat in the International System of Units (SI). It is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one meter.