- The definition of an outbreak is a sudden increase, outburst or riot.
An example of an outbreak is five cases of whooping cough increasing to fifty cases overnight.
outbreak definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
- a breaking out; sudden occurrence, as of disease or war
- an insurrection or riot
outbreak definition by American Heritage Dictionary
- A sudden increase: an outbreak of influenza.
- A sudden eruption; an outburst: “an outbreak of strikes, violent agitation, and arrests” (Samuel Chew).