interest

Etymology

From Middle English interest, from Old French interesse and interest (French intérêt), from Medieval Latin interesse, from Latin interesse.

noun

1. (uncountable, finance) The price paid for obtaining, or price received for providing, money or goods in a credit transaction, calculated as a fraction of the amount or value of what was borrowed.
   Our bank offers borrowers an annual interest of 5%.
2. (uncountable, finance) Any excess over and above an exact equivalent
3. (uncountable) A great attention and concern from someone or something; intellectual curiosity.
   He has a lot of interest in vintage cars.
   Thinks I to myself, “Sol, you're run off your course again. This is a rich man's summer ‘cottage’ and if you don't look out there's likely to be some nice, lively dog taking an interest in your underpinning.” 1913, Joseph C. Lincoln, chapter 1, in Mr. Pratt's Patients
4. (uncountable) Attention that is given to or received from someone or something.
   Over the past few years, however, interest has waxed again. A series of epidemiological studies, none big enough to be probative, but all pointing in the same direction, persuaded Emma Wilmot of the University of Leicester, in Britain, to carry out a meta-analysis. This is a technique that combines diverse studies in a statistically meaningful way. 2013-08-10, “Standing orders”, in The Economist, volume 408, number 8848
   Across Japan, technology companies and private investors are racing to install devices that until recently they had little interest in: solar panels. Massive solar parks are popping up as part of a rapid build-up that one developer likened to an "explosion." 2013-06-21, Chico Harlan, “Japan pockets the subsidy[…]”, in The Guardian Weekly, volume 189, number 2, page 30
5. (countable) An involvement, claim, right, share, stake in or link with a financial, business, or other undertaking or endeavor.
   When scientists and doctors write articles and when politicians run for office, they are required in many countries to declare any existing conflicts of interest (competing interests).
   I have business interests in South Africa.
   She has an interest in the proceedings, and all stakeholders' interests must be protected.
6. (countable) Something or someone one is interested in.
   Lexicography is one of my interests.
   Victorian furniture is an interest of mine.
   The main character's romantic interest will be played by a non-professional actor.
7. (uncountable) Condition or quality of exciting concern or being of importance.
   The conscience, indeed, is already violated when to moral good or evil we oppose things possessing no moral interest. 1809, Samuel Taylor Coleridge, The Friend, Essay VIII
8. (obsolete, rare) Injury, or compensation for injury; damages.
9. (usually in the plural) The persons interested in any particular business or measure, taken collectively.
   the iron interest;  the cotton interest

verb

1. To engage the attention of; to awaken interest in; to excite emotion or passion in, in behalf of a person or thing.
   It might interest you to learn that others have already tried that approach.
   Action films don't really interest me.
2. (obsolete, often impersonal) To be concerned with or engaged in; to affect; to concern; to excite.
   Or rather, gracious sir, / Create me to this glory, since my cause / Doth interest this fair quarrel. 1633, John Ford, Perkin Warbeck
3. (obsolete) To cause or permit to share.