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 McCarty notes that some studies have linked magnesium supplements to lower odds of short sleep duration and to modest improvements in sleep-onset latency in certain populations, McCarty cautions that the overall research remains mixed. —Sharon Brandwein, USA Today, 2 June 2026

There was the comeback in April-May 2020, directly after the onset of the Covid-19 pandemic; March-April 2009, which followed the Great Financial Crisis; and January-February 1975, following the first oil shock. —Sarah Min, CNBC, 2 June 2026

During the transition from the Pliocene to the Pleistocene, the North Sea experienced significant climatic shifts tied to the onset of ice ages. —Melissa Cristina Márquez, Forbes.com, 1 June 2026

The high-pressure increases that have given rise to higher temperatures have not sustained themselves, and often have been followed by significant drops in the barometric pressure and the onset of clouds and occasional rain. —Rick Hurd, Mercury News, 1 June 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