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

In the second, highly lethal variant of the Black Death, patients typically exhibited no initial symptoms, such as the onset of a fever or the appearance of buboes, but instead would suddenly begin to vomit up blood (that was usually dark in color) and typically died soon thereafter. —Literary Hub, 27 May 2026

Illness onset dates range from March 27 through April 30, 2026. —George Avalos, Mercury News, 25 May 2026

The loss has led to a sudden onset of grief at one of NASCAR’s signature weekends. —Kyle Feldscher, CNN Money, 24 May 2026

Situational depression is a form of depression that has as its onset a specific event or circumstance that triggers the bout of depression. —Lance Eliot, Forbes.com, 24 May 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