A deficit is the amount by which a sum falls short of some reference amount.
In economics, a deficit is an excess of expenditures over revenue in a given time period; in more specific cases it may refer to:
Balance of payments deficit, when the balance of payments is negativeGovernment budget deficitDeficit spendingPrimary deficit, the pure deficit derived after deducting the interest paymentsStructural and cyclical deficit, parts of the public sector deficitIncome deficit, the difference between family income and the poverty thresholdTrade deficit, when the value of imports exceed the value of exportsDeficit may also refer to:
Attention deficit hyperactivity disorder, a developmental disorder characterized by attentional problems and hyperactivityCognitive deficit, any characteristic that acts as a barrier to cognitive performanceDefect (geometry), angular deficitDéficit, a 2007 Mexican film by Gael García BernalSleep Deficit, a negative difference between an interval a person actually slept for, and the time they should have spent sleeping (8 hours per day) over certain period. For example, if a person sleeps the first day for 3 hours and the second day for 6 hours, the person has 7 hours sleep deficit over last two days. Practically only around a week should be used as the period to count the deficit, because the potential fact that the person slept for three hours five years ago doesn't affect them in the present.