It is interesting to note that, although many books are written about work, it is rare to find a clear definition. The word work is used often and in many different ways. The Oxford English Dictionary affords the term considerable space referring to expenditure of effort, striving, exertion of force in overcoming resistance, tasks to be undertaken, achievement, employment, earning money and to have influence or effect – to mention only a few.
The definition of work in the physical sciences is, of course, very clear – work = force × distance. We are concerned with a different form of work. Despite the many social meanings of the term work, we have found it useful to define human work as follows: