onset

noun

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

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.
While aging has been shown to be the biggest driver — and family history also increases the risk — research has shown that some lifestyle behaviors can help ward off or slow the onset of the disease. Melissa Rudy, FOXNews.com, 24 Oct. 2025 For someone with sleep-onset insomnia, Kat says, lights-out might have come earlier, and the scheme would have been different. Rowan Jacobsen, Harpers Magazine, 24 Oct. 2025 The onset of the Great Depression, which hit Germany’s fragile economy harder than most, heralded a rapid rise in street brawls among these groups. Time, 23 Oct. 2025 The advisories aim to offer time-sensitive precautions, minimize agricultural losses and protect infrastructure before the onset of winter weather patterns. Deputy News Editor, MSNBC Newsweek, 22 Oct. 2025 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

Cite this Entry

“Onset.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onset. Accessed 30 Oct. 2025.

Kids Definition

onset

noun
on·​set ˈȯn-ˌset How to pronounce onset (audio)
ˈän-

Medical Definition

onset

noun
: the initial existence or symptoms of a disease
the onset of scarlet fever

More from Merriam-Webster on onset

Last Updated: - Updated example sentences
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