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

Mortgage rates are certainly a factor among buyers when deciding to make an offer, and home prices are also up more than 50% since the onset of the pandemic, according to the U.S. Case-Shiller Home Price Index. —Sydney Lake, Fortune, 31 July 2025

According to many of the physicians who spoke with The Hollywood Reporter, video calls’ increasing pervasiveness since the onset of the pandemic in 2020 — termed the Zoom Boom among industry insiders — has been one of the most notable shifts in recent years. —Gary Baum, HollywoodReporter, 30 July 2025

Since the onset of the Covid pandemic, the 10-year rate has steadily climbed to about 4.5%, helping lift mortgage rates to about 6.5%. —Shannon Pettypiece, NBC news, 29 July 2025

This behavior has been accelerating since the onset of Covid-19, when many consumers retreated to staple products and brands. —Chris Fosdick, Forbes.com, 25 July 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