[on-set, awn-]


a beginning or start: the onset of winter.
an assault or attack: an onset of the enemy.
Phonetics. the segment of a syllable preceding the nucleus, as the gr in great.Compare coda(def 5), core1(def 14).

Origin of onset

1525–35; on + set, after the verb phrase set on
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for onset

Contemporary Examples of onset

Historical Examples of onset

British Dictionary definitions for onset



an attack; assault
a start; beginning
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for onset

1530s, "attack, assault," from on + set (n.); cf. to set (something) on (someone). Weaker sense of "beginning, start" first recorded 1560s. Figurative use in reference to a calamity, disease, etc. is from 1580s.

Online Etymology Dictionary, © 2010 Douglas Harper

onset in Medicine




A beginning; a start, as of a cold.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.