What is "budget constraint"

n. (context economics English) The condition that constrains expenditure to income (for a person) or the value of exports to imports (for a state)

A budget constraint represents all the combinations of goods and services that a consumer may purchase given current prices within his or her given income. Consumer theory uses the concepts of a budget constraint and a preference map to analyze consumer choices. Both concepts have a ready graphical representation in the two-good case.