In the world of business, a commodity is an undifferentiated product whose value arises from the owner's right to sell rather than the right to use. Example: commodities from the financial world include oil (sold by the barrel), electricity (most users of electric power are only concerned with overall energy consumption; only a minority of users are concerned with the quality and technical details of voltage and frequency deviations, phase imbalance, etc.), wheat, bulk chemicals such as sulfuric acid, base and other metals, and even pork-bellies and orange juice. More modern commodities include bandwidth, RAM chips and (experimentally) computer processor cycles, and negative commodity units like emissions credits.
In the original and simplified sense, commodities were things of value, of uniform quality, that were produced in large quantities by many different producers; the items from each different producer are considered equivalent. It is the contract and this underlying standard that define the commodity, not any quality inherent in the product. One can reasonably say that food commodities, for example, are defined by the fact that they substitute for each other in recipes, and that one can use the food without having to look at it too closely.