onset

noun

on·​set ˈȯn-ˌset 

ˈän-

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

• attack
• assault
• onslaught
• raid
• offensive
• aggression
• offense
• strike

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

That isolation was compounded because he was diagnosed just as the country locked down at the onset of the COVID-19 pandemic, Bullock said. — Theresa Braine, New York Daily News, 20 Aug. 2026

In the months before his dismissal, Fedorov pursued numerous high-tech plans to force the Russians to negotiate before the onset of winter. — Simon Shuster, The Atlantic, 20 Aug. 2026

And while early-onset Alzheimer’s is rare, that doesn’t mean women should ignore changes that genuinely concern them. — Lauryn Higgins, Flow Space, 19 Aug. 2026

Chronic absenteeism – referring to students who miss 10% or more days of the school year – has become one of the most urgent problems across American schools since the onset of the COVID-19 pandemic in 2020. — Jerome A. Graham, The Conversation, 19 Aug. 2026

Word History

First Known Use

circa 1522, in the meaning defined at sense 1

Phrases Containing onset

• adult-onset diabetes
• juvenile-onset diabetes

Rhymes for onset

• abet
• asset
• baguette
• banquette
• barbette
• beget
• beset
• binet
• briquette
• brunet
• brunette
• burette

Kids Definition

onset

noun

on·​set ˈȯn-ˌset 

ˈän-

1

: attack entry 2 sense 1

2

: beginning sense 1

Medical Definition

onset

noun

on·​set ˈȯn-ˌset, ˈän- 

: the initial existence or symptoms of a disease

the onset of scarlet fever