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 effects are social and calm with a 20-minute onset that lasts for an hour of pleasantness. — Angela Hansberger, AJC.com, 6 July 2026

There is usually a delay between the onset of the event and many of the associated effects. — ABC News, 9 July 2026

Most of the symbol is believed to have been torn down by patriots at the onset of the revolution, though the surviving third remains at the church. — Lianne Kolirin, CNN Money, 8 July 2026

Once infected, a person usually begins experiencing symptoms about a week later, though onset can range from two days to over two weeks. — Beth Mole, ArsTechnica, 9 July 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