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

• attack
• onslaught
• raid
• assault
• strike
• attempt

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

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

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