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

The researchers also discovered that Whitney’s brain had virtually no buildup of tau, the hallmark protein that signals the onset of cognitive decline. —Melissa Rudy, FOXNews.com, 14 Oct. 2025

An introduction to the press in November 2019 netted immediate e-commerce sales but Nomasei was waylaid by the onset of the COVID-19 pandemic, four months in. —Lily Templeton, Footwear News, 14 Oct. 2025

Autumn has draped itself across the northern hemisphere, heralding the onset of longer, darker nights that serve as the perfect backdrop for amateur astronomers looking to explore the wonders of the night sky. —Anthony Wood, Space.com, 14 Oct. 2025

However, Brundle thinks the other teams will be quick to prevent another team from entering the sport, especially with the onset of a new era of regulations in 2026. —Saajan Jogia, MSNBC Newsweek, 14 Oct. 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