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

This was already understood by the onset of the 1970s, prompting countless network executives to kill themselves in the hope of creating something impeccably suited for sitting in front of an electromagnetic box and remaining there for as long as possible. —Los Angeles Times, 22 Jan. 2026

The authors of the report noted these findings highlight the need for more research to identify causes for increasing early-onset colorectal cancer. —Sara Moniuszko, USA Today, 22 Jan. 2026

The sudden onset of freezing temperatures may damage the plants. —Luke Miller, Better Homes & Gardens, 19 Jan. 2026

While still 4-5 days out, most of our long-range modeling brings rain at the onset on Friday, with highs still near 50. —Michael Autovino, CBS News, 19 Jan. 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
• 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