Hi Davidyson,

You're actually describing two separate notions here. 'Demand' is actually pretty well defined in Economics. When an economist speaks of 'Demand,' he/she is usually referring to the amount of goods (or services) that a consumer is willing to purchase at a variety of price points. This is typically represented by a curve on a graph, hence the term 'demand curve' which you may hear in these types of discussions.

Another often-used term is 'quantity demanded.' Perhaps as its name implies, this is the amount of goods (or services) that a consumer demands at a particular price point.

Unfortunately, this definition tends to differ slightly from the every day use of the term which to me implies a certain emotional component which can't be easily quantified. Joseph gives a good example in his post following yours.

The crux of the communication issue in my opinion is not that lay people tend to use different definitions, it is that they do not define their terms sufficiently rigorously. With a good enough definition you could define demand to mean anything at all and if you use it in a sentence I'll be able to understand what you mean.

As for your other point on business investment, you bring up a very good point, but unfortunately exploring how the various actors in the supply chain will be affected by an increase in the price of a commodity is actually a pretty complex endeavor.