Any financial shortfall, whether cumulative or for a single period.
2. Public finances.
A government fiscal deficit, usually for a particular period, most often a year.
3. Pensions - defined benefit schemes.
The accumulated excess of liabilities over assets in a funded Defined benefit pension scheme; also known as under-funding.
Pension liabilities = 100.
Pension assets = 90.
The deficit would be:
100 - 90
(Not to be confused with the percentage funding level which in this example would be 90 / 100 = 90%.)
Relevant accounting standards include Section 28 of FRS 102.