In the realm of income tax, the term "deduction" refers to an item that is subtracted from taxable income, resulting in a reduction of said income. Essentially, deductions are used to lower the amount of income that is subject to taxation. This can include expenses such as medical bills, charitable donations, and mortgage interest. By understanding how deductions work, individuals can effectively manage their taxable income and potentially reduce their tax liability. So, it is crucial to have a clear understanding of this term in the realm of finance.