anom·​a·​lous ə-ˈnä-mə-ləs How to pronounce anomalous (audio)
: inconsistent with or deviating from what is usual, normal, or expected : irregular, unusual
Researchers could not explain the anomalous test results.
: of uncertain nature or classification
an anomalous figure in the world of politics
: marked by incongruity or contradiction : paradoxical
anomalously adverb
anomalousness noun
Choose the Right Synonym for anomalous

irregular, anomalous, unnatural mean not conforming to rule, law, or custom.

irregular implies not conforming to a law or regulation imposed for the sake of uniformity in method, practice, or conduct.

concerned about his irregular behavior

anomalous implies not conforming to what might be expected because of the class or type to which it belongs or the laws that govern its existence.

her drive made her an anomalous figure in a sleepy organization

unnatural suggests what is contrary to nature or to principles or standards felt to be essential to the well-being of civilized society.

prisoners treated with unnatural cruelty

Example Sentences

Researchers could not explain the anomalous test results. that was an anomalous year for the housing industry, so the number of starts is anything but typical
Recent Examples on the Web What ultimately made our team go back to replicate Penfield’s original work was a set of anomalous findings using a specialized type of MRI that identifies brain networks dedicated to a particular function. Nico U.f. Dosenbach, Scientific American, 21 Apr. 2023 Lin, whose study at AGU this week was co-authored by hurricane research eminence Kerry Emanuel of MIT, said that predicting these anomalous storms just requires a different approach. IEEE Spectrum, 14 Mar. 2023 Playwright Tina Satter’s Is This a Room is one of the more anomalous standouts of recent New York theater seasons. David Rooney, The Hollywood Reporter, 18 Feb. 2023 Before this, a radar operator in the group had been picking up anomalous aerial vehicles (AAVs) — the Navy's term for UAPs — for several days at an altitude of over 80,000 feet. Monica Cull, Discover Magazine, 26 Oct. 2022 Suddenly, there was a large, anomalous plume of fire from the rocket's engine, and the escape motor on board the spacecraft fired. Eric Berger, Ars Technica, 12 Sep. 2022 An anomalous late summer Nor'easter will impact eastern Massachusetts tonight & Wednesday, with strong winds & heavy rain for Cape Cod & the Islands. Jeremy C. Fox,, 16 Aug. 2022 On Tuesday, President Biden named the senior director for intelligence programs at the National Security Council, Maher Bitar, to officially serve as the government's anomalous health incident interagency coordinator. Olivia Gazis, CBS News, 3 Feb. 2022 But there is far more to these anomalous animals than that. Tim Flannery, The New York Review of Books, 2 Feb. 2023 See More

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

Word History


Late Latin anōmalus "irregular (of grammatical paradigms), unequal in size (of planets)" (borrowed from Greek anṓmalos "not uniform, unequal, inconsistent, irregular [in grammar]," from an- an- + homalόs "even, uniform, equal, like") + -ous — more at similar

First Known Use

1606, in the meaning defined at sense 1

Time Traveler
The first known use of anomalous was in 1606

Dictionary Entries Near anomalous

Cite this Entry

“Anomalous.” Dictionary, Merriam-Webster, Accessed 10 Jun. 2023.

Kids Definition


anom·​a·​lous ə-ˈnäm-ə-ləs How to pronounce anomalous (audio)
: not following a general rule or method : irregular, unusual
anomalously adverb
anomalousness noun

Medical Definition


anom·​a·​lous ə-ˈnäm-ə-ləs How to pronounce anomalous (audio)
: deviating from normal
anomalous development
anomalous pulmonary venous drainagePhysicians' Current Procedural Terminology
specifically : having abnormal vision with respect to a particular color but not color-blind
she was almost red anomalous Nature

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