Aggregate Demand

What Does Aggregate Demand Mean?
The total amount of goods and services demanded in the economy at a given overall price level and in a given time period. It is represented by the aggregate-demand curve, which describes the relationship between price levels and the quantity of output that firms are willing to provide. Normally there is a negative relationship between aggregate demand and the price level. Also known as "total spending".

Investopedia explains Aggregate Demand
Aggregate demand is the demand for the gross domestic product (GDP) of a country, and is represented by this formula:

Aggregate Demand (AD) = C + I + G (X-M)   C = Consumers' expenditures on goods and services. I = Investment spending by companies on capital goods. G = Government expenditures on publicly provided goods and services. X = Exports of goods and services. M = Imports of goods and services.