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

In order to create stars, the Universe needed to create neutral atoms, which were produced about 380,000 years after the onset of the hot Big Bang. —Ethan Siegel, Big Think, 16 Sep. 2025

At the onset of Prohibition, about 210 distilleries operated in Kentucky, Morris said, but only about a half dozen of them received licenses. —Maggie Menderski, Louisville Courier Journal, 16 Sep. 2025

In those 15 seconds, later described by his teammates, Jones offered a defining line separating the end of 2024 and the onset of 2025 — and the onset of a journey statistically more improbable than defending a Super Bowl title. —Sam McDowell, Kansas City Star, 12 Sep. 2025

But Operation Warp Speed delivered shots within a year of the pandemic’s onset and is credited with saving millions of American lives, according to a study by the Commonwealth Fund. —Jeffrey Kopp, CNN Money, 12 Sep. 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