on·​set | \ ˈȯn-ˌset How to pronounce onset (audio) , ˈän-\

Definition of onset

1 : attack, assault withstand the onset of the army
2 : beginning, commencement the onset of winter the onset of age-related diseases

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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

Federer made his intentions known from the onset, coming in frequently and fruitfully on Evans’ slice backhand and limiting the errors that plagued him in those earlier matches. Daniel Rapaport, SI.com, "Federer, Serena Rounding Into Form Ahead U.S. Open's Second Week," 30 Aug. 2019 Mueller has repeatedly cited a Justice Department Office of Legal Counsel memo, which advises against the indictment of a sitting president, as something that from the onset of his probe made an indictment impossible. Allan Smith, NBC News, "Mueller pressed on how his inability to declare a crime took place doesn’t amount to an exoneration," 25 July 2019 Betty, 76, was one -- a partially blind and homeless woman suffering from the onset of dementia last fall. oregonlive.com, "Report: Hospital calls about ‘unwanted’ people trespassing leads to jail, criminalizing mental illness," 18 June 2019 From the onset of the modern culture war, the campus has represented the epicenter of illiberal leftist power. David French, National Review, "Against Conservative Cultural Defeatism," 4 June 2019 But as days get shorter with the onset of fall, noctilucent clouds will fade from view. Andrew Fazekas, National Geographic, "Perseids peak, and more top stargazing events in August," 1 Aug. 2019 For many girls, migraine starts with the onset of puberty. Anne Saker, Cincinnati.com, "Puberty and migraines have an early connection for girls, UC study finds," 16 July 2019 To date, more than 90% of those with AFM report having a mild respiratory infection or fever right before the onset of limb weakness. Beth Mole, Ars Technica, "Mysterious illness that paralyzes healthy kids prompts plea from CDC," 10 July 2019 With the onset of World War II, Henry enlisted in the Navy at age 15, using the name of a relative a few years older. New York Times, "Dr. Henry Lynch, 91, Dies; Found Hereditary Link in Cancer," 13 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'onset.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of onset

circa 1522, in the meaning defined at sense 1

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Statistics for onset

Last Updated

9 Sep 2019

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Time Traveler for onset

The first known use of onset was circa 1522

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More Definitions for onset



English Language Learners Definition of onset

: the beginning of something


on·​set | \ ˈȯn-ˌset How to pronounce onset (audio) , ˈän-\

Kids Definition of onset

1 : beginning sense 1 the onset of winter


on·​set | \ ˈȯn-ˌset, ˈän- How to pronounce onset (audio) \

Medical Definition of onset

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

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More from Merriam-Webster on onset

Rhyming Dictionary: Words that rhyme with onset

Thesaurus: All synonyms and antonyms for onset

Spanish Central: Translation of onset

Nglish: Translation of onset for Spanish Speakers

Britannica English: Translation of onset for Arabic Speakers

Comments on onset

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miscellaneous remnants or debris

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