Definitions from Wordnet 2.0

• the property of being an amount by which something is less than expected or required
• an excess of liabilities over assets (usually over a certain period)

Definitions from Wiktionary

• the property of being an amount by which something is less than expected or required; "new blood vessels bud out from the already dilated vascular bed to make up the nutritional deficit" ,
• a deficiency or failure in neurological or mental functioning; "the people concerned have a deficit in verbal memory"; "they have serious linguistic deficits" ,
• (sports) the score by which a team or individual is losing ,
• an excess of liabilities over assets (usually over a certain period); "last year there was a serious budgetary deficit"

• Deficit: A deficit is the amount by which a sum falls short of some reference amount. In economics, a deficit is a shortfall in revenue; in more ...
• Government budget deficit: A government budget deficit is the amount by which some measure of government revenues falls short of some measure of government spending. ...
• Deficit spending: Deficit spending is the amount by which a government, private company, or individual's spending exceeds income over a particular period of ...
• Cognitive deficit: Cognitive deficit, also known as cognitive impairment is an inclusive term to describe any characteristic that acts as a barrier to ...
• Primary deficit: Primary deficit is the deficit which is derived after deducting the interest payments component from the total deficit of any budget. ...