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

Research suggests this disruption may stem from alterations in normal neurodevelopmental processes that happen as adolescents mature — especially since the higher end of the typical age range of onset is when the brain completes maturation, D’Souza said. —Kristen Rogers, CNN Money, 2 Sep. 2025

Drought can delay the onset of color, while moist soil, in tandem with the right late-summer weather, produces good displays, Crick wrote. —Jim Higgins, jsonline.com, 2 Sep. 2025

Our own planet’s active geology squelched our ability to retain a full history of the onset of life. —Bruce Dorminey, Forbes.com, 2 Sep. 2025

There’s some thought that an increase in diagnoses of early-onset colorectal cancer could be exacerbated by differences in screening for younger versus older patients. —Caroline C. Boyle, USA Today, 2 Sep. 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