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 Asia, a global dip in radiance in early 2020 aligned almost precisely with the onset of COVID-19 lockdowns. —Bree Shirvell, Hartford Courant, 12 May 2026

The House of Representatives eliminated the pandemic-era proxy voting rules, implemented under Pelosi at the onset of the coronavirus pandemic, when the GOP gained control of the lower chamber of Congress in January 2023. —Jack Birle, The Washington Examiner, 12 May 2026

The Dome closed in March 2020 with the onset of the COVID-19 pandemic and in April 2021 it was announced that the venue would not be reopening. —Los Angeles Times, 12 May 2026

That drop in core temperature is one of the body’s key signals for sleep onset — a process called distal vasodilation. —Allison Palmer, Kansas City Star, 12 May 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