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

This ensures that, when inflation ends, the majority of entropy in the volume of the Universe that becomes our observable Universe comes from the end of inflation and the onset of the hot Big Bang. —Big Think, 9 Apr. 2026

Gowdy estimates that about 16 youth treatment programs have shuttered since the onset of the pandemic. —CBS News, 8 Apr. 2026

Take zinc at the onset of a cold, ideally within 24 hours of developing symptoms such as sneezing, coughing, nasal congestion, or sore throat. —Megan Nunn, Verywell Health, 8 Apr. 2026

Simple lifestyle changes could reduce a person’s risk of late-onset dementia by as much as 25%, according to the study. —Kaitlin Sullivan, NBC news, 8 Apr. 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