What is Work ?
Understanding the work’s basis is very recent, so it is difficult to understand. Work is producing projects. A project is a goal to achieve, with a beginning and an end. You probably know it a little, probably without being told.
In economics, we now know that work is provided by energy. But what is energy? Well when you work you move and you can be hot. Heat is an energy production. When the air is hot, it means that the sun has brought energy to earth.
The economy measures how to produce useful work. We now know that economics measures energy to make things. The more energy is dense on one point, the more works can be done.
Read the beginning of Nicolas Léonard Sadi Carnot’s book, on wikisource.