die-off

American  

[dahy-awf, -of] / ˈdaɪˌɔf, -ˌɒf /

noun

1. a sudden, natural perishing of large numbers of a species, population, or community.

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die-off Scientific  

/ dī′ôf′ /

1. 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.

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die off Idioms  

1. Perish one by one, as in A celibate community, the Shakers are dying off. [Late 1600s]

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Etymology

Origin of die-off

First recorded in 1935–40; noun use of verb phrase die off

Example Sentences

These toxic elements sat in the channel’s then-stagnant water, which led to a die-off of all vegetation and the emission of foul-smelling hydrogen sulfide.

From Los Angeles Times • Feb. 7, 2026

"Reports from elsewhere suggest that the 2022-2023 die-off in the Canary Islands was another step in a broader marine pandemic, with serious consequences for these key reef grazers," concluded Cano.

From Science Daily • Dec. 12, 2025

Earlier this year, scientists warned that bird flu had sparked the worst die-off on record for southern elephant seals when it spread among a population on Argentina's coast in 2023.

From Barron's • Nov. 13, 2025

But the whelk is a cold-water species, and a marine heatwave in 2022 triggered a mass die-off of these snails in the Thames Estuary.

From BBC • Aug. 10, 2025

The die-off happened amazingly fast—the statistics, according to the study, suggest that it was instantaneous.

From "1491" by Charles C. Mann

Related Words

• abate
• decrease
• diminish
• dwindle
• ebb
• fade
• fall back
• lessen
• reduce
• retreat
• shrink
• sink
• subside
• taper
• wane