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

In the luteal phase, rising body temperature can delay sleep onset because the body needs a core temperature drop to fall asleep effectively. —Allison Palmer, Fort Worth Star-Telegram, 8 June 2026

During her senior year, Mitrovich was sent home from college in March 2020, amid the onset of the COVID-19 pandemic. —Tabitha Parent, PEOPLE, 8 June 2026

At the onset of the 1990s, the Berlin wall had fallen, and the USSR had broken up. —Edward Lotterman, Twin Cities, 7 June 2026

There are currently no treatment options between the onset of a heart attack and the first contact with a medical provider. —Justin Zacks, CNBC, 4 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