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

There is usually a delay between the onset of El Nino and its peak impact on global temperatures, NOAA says. — Dan Peck, ABC News, 13 Aug. 2026

Chan directs Zhou Xun, Wen Qi, Tian Zhuangzhuang and Wang Xiao in the drama, which centers on early-onset Alzheimer disease. — Naman Ramachandran, Variety, 12 Aug. 2026

At 51, Rabatin was a few years shy of the average age of onset, which is 55. — Beth Sobol, Flow Space, 12 Aug. 2026

In this case, a critical risk for fire comes from the forecast rapid onset of strong outflow winds gusting above 30 mph, coupled with the potential for lightning. — Sean MacAday, Sacbee.com, 12 Aug. 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