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

Wearable-device features that flag when your evening workout is delaying your own sleep onset — not the population average. — Lauren Jarvis-Gibson july 23, Miami Herald, 23 July 2026

The Mayo Clinic states that early-onset Alzheimer’s disease is a rare form of dementia that affects people younger than age 65. — Gina Kalsi, PEOPLE, 22 July 2026

The median illness onset date was June 26, 2026 (range from May 1 to July 16). — Mike Snider, USA Today, 22 July 2026

The movie houses closed at the onset of the pandemic in 2020. — Gary Baum, HollywoodReporter, 21 July 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