used to express surprise, triumph, or derision
"Aha! we've found the thief, then!" said the conductor.Horatio Alger
The Professor smiled, and looked quite jubilant. He rubbed his hands together, and said, "Aha! I thought I had diagnosed the case. My treatment is working."Robert Louis Stevenson
"Aha! Doctor!" said the Colonel at last, with a doltish sneer, "you bear your years well."Nathaniel Hawthorne
see also aha moment


2 of 2

abbreviation or noun

plural AHAs
: alpha hydroxy acid
The product also includes 6 percent alpha hydroxy acid (AHA), an exfoliator, to enhance the growth of new healthy skin.Dermatology Times
AHAs loosen the bonding between the outermost skin cells, encouraging them to slough off and reveal the fresh new skin beneath.Essence

Examples of aha in a Sentence

Interjection aha! so the money was never missing in the first place!
Recent Examples on the Web
For example, problem 24 asks for the value of aha if aha plus one-seventh of aha equals 19. Peter Schumer, Smithsonian Magazine, 4 Aug. 2023 This was an ‘aha’ moment for the field of social psychology — the researchers had identified a quantifiable measure of social connection. Gabe Allen, Discover Magazine, 7 Mar. 2022 My twins, August looks to be a month of revelations, and aha moments will abound! Meghan Rose, Glamour, 1 Dec. 2022 However, Clodfelter provided enough insights so that some delegates might have their own ‘aha’ moment when pitching the studio. Liza Foreman, Variety, 15 Oct. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'aha.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History



Middle English

First Known Use


14th century, in the meaning defined above

Abbreviation Or Noun

1991, in the meaning defined above

Time Traveler
The first known use of aha was in the 14th century

Dictionary Entries Near aha

Cite this Entry

“Aha.” Dictionary, Merriam-Webster, Accessed 22 Sep. 2023.

Kids Definition


used to express surprise, triumph, or scorn

Medical Definition


1 of 2 abbreviation or noun


2 of 2 abbreviation
American Heart Association
American Hospital Association
Last Updated: - Updated example sentences
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