ETYM Old Fren. interest, French intéręt, from Latin interest it interests, is of interest, from interesse to be between, to be difference, to be importance; inter between + esse to be; cf. Late Lat. interesse usury. Related to Essence.
1. A sense of concern with and curiosity about someone or something; SYN. involvement.
2. The power of attracting or holding one's interest (because it is unusual or exciting etc.); SYN. interestingness.
3. A right or legal share of something; a financial involvement with something; SYN. stake.
4. A fixed charge for borrowing money; usually a percentage of the amount borrowed.
5. (Usually plural) A social group whose members control some field of activity and who have common aims; SYN. interest group.
In finance, a sum of money paid by a borrower to a lender in return for the loan, usually expressed as a percentage per annum. Simple interest is interest calculated as a straight percentage of the amount loaned or invested. In compound interest, the interest earned over a period of time (for example, per annum) is added to the investment, so that at the end of the next period interest is paid on that total.
A sum of $100 invested at 10% per annum simple interest for five years earns $10 a year, giving a total of $50 interest (and at the end of the period the investor receives a total of $150). The same sum of $100 invested for five years at 10% compound interest earns a total of $61.05 interest (with $161.05 returned at the end of the period). The difference arises from adding the previous period's interest to the capital before calculating the next payment.
To excite the curiosity of; engage the interest of.