In economics, a shortage or excess demand is a situation in which the demand for a product or service exceeds its supply in a market. It is the opposite of an excess supply (surplus).
Unemployed men queue outside a depression soup kitchen in United States during the Great Depression.
A 2014 image of product shortages in Venezuela
Empty supermarket shelves in the dry pasta section due to panic-buying as the result of the 2020 COVID-19 outbreak
In economics, market clearing is the process by which, in an economic market, the supply of whatever is traded is equated to the demand so that there is no excess supply or demand, ensuring that there is neither a surplus nor a shortage. The new classical economics assumes that in any given market, assuming that all buyers and sellers have access to information and that there is no "friction" impeding price changes, prices constantly adjust up or down to ensure market clearing.
In retail stores, when a business ends up with too much of a certain product, which remains unsold at its longstanding price (such as unsold summer clothing as the colder season approaches), the store will typically discount the price until the excess stock is sold, a simple example of "market clearing."