onset

noun

on·​set ˈȯn-ˌset How to pronounce onset (audio)
ˈän-
Synonyms of onset
1
: attack, assault
withstand the onset of the army
2
: beginning, commencement
the onset of winter
the onset of age-related diseases

Synonyms of onset

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Examples of onset in a Sentence

the walls withstood the onset of the first battalion the claim that if you take enough vitamin C at the onset of a cold, you'll often recover faster
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
With the onset of the autumn agricultural harvest and winter heating seasons, domestic distillate inventories, including diesel, continue to trend downward. — CNBC, 7 Oct. 2026 This meant that a succession of actors played Arnold over the years, until their voices changed with the onset of puberty. — Darryn King, Los Angeles Times, 7 Oct. 2026 Rabies is nearly 100% fatal after the onset of symptoms, and humans are generally exposed via the saliva of wild animals. — Eva Flowe october 7, Charlotte Observer, 7 Oct. 2026 The show picks up in the 1940s, well before the onset of the Pop movement, with Lichtenstein’s time as a graduate student at Ohio State University. — Alex Greenberger, ARTnews.com, 7 Oct. 2026 See All Example Sentences for onset

Word History

First Known Use

circa 1522, in the meaning defined at sense 1

Time Traveler
The first known use of onset was circa 1522

Phrases Containing onset

Rhymes for onset

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Browse Nearby Words

onsen
onset
onsetter
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Cite this Entry

“Onset.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onset. Accessed 14 Oct. 2026.

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Kids Definition

Medical Definition

onset

noun
on·​set ˈȯn-ˌset, ˈän- How to pronounce onset (audio)
: the initial existence or symptoms of a disease
the onset of scarlet fever
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