C

Canceled Debt
Forgiven debt on a mortgage or other loan. Canceled debt is generally considered taxable income.
Capital Gain
Profit from the sale or trade of an investment property such as stock or real estate.
Casualty Loss
A deduction taken for property damage suffered during a disaster or other such event.
Child Support
Payments made to an ex-spouse or legally separated spouse for the care of a child. Child support payments are generally neither taxable nor deductible.
COBRA
The part of the Consolidated Omnibus Budget Reconciliation Act of 1985 that, in many cases, provides continuation of employer sponsored health insurance for workers who have lost their jobs.
Combat Pay
Income earned while serving in a federally declared combat zone. Combat pay is generally nontaxable.
Community Property
A law in certain states pertaining to married couples which stipulates that income and property are owned equally by both spouses.
Constructive Receipt
The legal concept that income is taxed at the time it is received, whether or not you have actually cashed the check or withdrawn the funds from your account.
Coverdell Education Savings Account (ESA)
A tax deductible savings account containing funds for educational expenses. Interest and qualified withdrawals are generally nontaxable. 
Credit
A dollar-for-dollar reduction of your taxes owed. Some credits are refundable.