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

The family disclosed that Hilton's children, niece, and sister witnessed the onset of the crisis inside the home before fleeing the scene to prevent the children from witnessing further trauma. — Manuel Bojorquez, CBS News, 6 Aug. 2026

Design devices to be secure from the onset and establish practices to deliver timely remediations when vulnerabilities surface. — Thomas Ryd, Forbes.com, 6 Aug. 2026

Postpartum psychosis is a rare but serious medical emergency characterized by severe, rapid onset psychiatric episodes such as mania, depression or hallucinations in the days or weeks after birth. — Peter Charalambous, ABC News, 5 Aug. 2026

Beyond the frosted-glass door, which reflected the onset of dusk, the sound of a bicycle bell passed by. — Cynthia Zarin, Harpers Magazine, 4 Aug. 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