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

Measles can be transmitted by an infected person from four days prior to the onset of the rash to four days after the rash erupts. —Gillian Stawiszynski, Cincinnati Enquirer, 14 Jan. 2026

Along with this investigation on the agenda this evening, there were also a lot of residents who spoke up during public comment at the onset of the meeting, calling for unity and action in the new year. —Charlie Lapastora, CBS News, 14 Jan. 2026

The onset of elevated inflation alongside sluggish hiring in recent months had put the Fed in a difficult position, even before the DOJ opened a probe into Powell. —Max Zahn, ABC News, 13 Jan. 2026

Taking zinc supplements after the onset of initial symptoms can help block viral replication. —Ayesha Gulzar, Verywell Health, 13 Jan. 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
• brevet
• 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