in·ter·est (ĭntrĭst, -tər-ĭst, -trĕst′)
a. A state of curiosity or concern about or attention to something: an interest in sports.
b. Something, such as a quality, subject, or activity, that evokes this mental state: counts the theater among his interests.
2. often interests Regard for one's own benefit or advantage; self-interest: It is in your best interest to cooperate. She kept her own interests in mind.
a. A right, claim, or legal share: an interest in the new company.
b. Something in which such a right, claim, or share is held: has interests overseas.
c. A person or group of persons holding such a right, claim, or share: a petroleum interest.
4. Involvement with or participation in something: She has an interest in the quality of her education.
a. A charge for a loan, usually a percentage of the amount loaned.
b. An excess or bonus beyond what is expected or due.
a. An interest group.
b. The particular cause supported by an interest group.
tr.v. in·ter·est·ed, in·ter·est·ing, in·ter·estsIdiom:
1. To arouse the curiosity or hold the attention of: Your opinions interest me.
2. To cause to become involved or concerned with: tried to interest her in taking a walk.
3. Archaic To concern or affect.
in the interest/interests of
To the advantage of; for the sake of: thinking in the interest of the whole family; ate breakfast on the train in the interest of time.
[Middle English, from Old French, from Latin, it is of importance, third person sing. present tense of interesse, to be between, take part in : inter-, inter- + esse, to be; see es- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.