a sudden, natural perishing of large numbers of a species, population, or community.
Origin of die-off
First recorded in 1935–40; noun use of verb phrase die off
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
A sudden, severe decline in a population or community of organisms as a result of natural causes. Local die-offs can be caused by such factors as an unusual or extreme weather pattern, an outbreak of disease, or toxic algal blooms in a body of water. Widespread or global die-offs in which a species or group of species becomes extinct are generally associated with rapid climate change or other large-scale environmental dislocations.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.