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

While dealing with the closure of Shanghai Disneyland amid the onset of the COVID-19 pandemic, Chapek and Iger — who stayed with the company as executive chairman — sat for an interview with CNBC about the transition. — Patrick Connolly, The Orlando Sentinel, 1 Nov. 2026

Andrey Ganopolski, a physicist at the Potsdam Institute for Climate Impact Research, said there has been plenty of research into whether carbon pollution may significantly delay the onset of the next ice age. — Laura Paddison, CNN Money, 29 Oct. 2026

The New Yorker named this novel — about a man who discovers a manuscript secretly written by his wife, who has early-onset Alzheimer’s — one of the best books of 2026. — Prashant Rao, semafor.com, 29 Oct. 2026

Amid the onset of Parkinson’s disease, Lincoln retired from the museum in 2014. — Bob Goldsborough, Chicago Tribune, 28 Oct. 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