2
: beginning, commencement
the onset of winter
the onset of age-related diseases
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
Exercise increases core temperature, leading to a more rapid decline in temperature post-exercise, hastening sleep onset and deepening sleep.
—
Jesse Pines, Forbes, 4 Mar. 2025
Cowart’s mother, Faye Cowart, has early onset Alzheimer’s and struggles with being in a new place.
—Alicia Victoria Lozano, NBC News, 4 Mar. 2025
With the onset of March, UConn (20-9, 12-6 in the Big East), is suddenly looking like a team in which the pieces fit together.
—Dom Amore, Hartford Courant, 1 Mar. 2025
As a Rule 5 pick, Workman must be on the big-league roster at the onset of the season — and remain there through the end — otherwise he would be offered back to the Detroit Tigers, the organization that took him in the fourth round of the 2020 draft.
—Meghan Montemurro, Chicago Tribune, 1 Mar. 2025
See All Example Sentences for onset
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Jesse Pines, Forbes, 4 Mar. 2025
Cowart’s mother, Faye Cowart, has early onset Alzheimer’s and struggles with being in a new place.
—Alicia Victoria Lozano, NBC News, 4 Mar. 2025
With the onset of March, UConn (20-9, 12-6 in the Big East), is suddenly looking like a team in which the pieces fit together.
—Dom Amore, Hartford Courant, 1 Mar. 2025
As a Rule 5 pick, Workman must be on the big-league roster at the onset of the season — and remain there through the end — otherwise he would be offered back to the Detroit Tigers, the organization that took him in the fourth round of the 2020 draft.
—Meghan Montemurro, Chicago Tribune, 1 Mar. 2025
See All Example Sentences for onset
Cite this Entry
“Onset.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/onset. Accessed 12 Mar. 2025.
Copy CitationKids Definition
onset
noun
on·set
ˈȯn-ˌset 
ˈän-
Medical Definition
onset
noun
on·set
ˈȯn-ˌset, ˈän-
: the initial existence or symptoms of a disease
the onset of scarlet fever
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