Interest expense is defined as the cost for borrowing funds.
Interest expense is charged by the lender to the borrower and is a non-operating expense. This cost is normally determined by calculating the rate of interest on the remaining amount of the debt, and can be used to define interest charged on any type of borrowing.
This can range from lines of credit, bonds and loans. When receiving an income statement, the interest expense will display as the amount charged during the specific period, as opposed to the amount paid during said interval.
For interest expenses, they do tend to be tax-deductible for businesses, however that can vary on a case-by-case basis for individuals. Some of the things that factor into whether it would or would not be tax-deductible for an individual would be their jurisdiction as well as the purpose of the loan itself. If you are curious to see if your interest expense is indeed eligible for tax deduction, be sure to do your due diligence to research and confirm.