: the amount of a toxic agent (such as a poison, virus, or radiation) that is sufficient to kill 50 percent of a population of animals usually within a certain time

Examples of LD50 in a Sentence

Recent Examples on the Web Native to Australia, this snake has the deadliest venom based on median lethal dose, or LD50, tests on mice. Olivia Munson, USA TODAY, 24 Sep. 2022 The Novichok nerve agents’ estimated LD50 may be as low as 4,000 ng/kg — deadlier than tetradotoxin, but nowhere close to botulinum’s lethality. Gemma Tarlach, Discover Magazine, 25 Sep. 2018

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'LD50.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

lethal dose

First Known Use

1942, in the meaning defined above

Time Traveler
The first known use of LD50 was in 1942

Dictionary Entries Near LD50

Cite this Entry

“LD50.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/LD50. Accessed 19 Jul. 2024.

Medical Definition

LD50

noun
variants or LD50
: the amount of a toxic agent (as a poison, virus, or radiation) that is sufficient to kill 50 percent of a population of animals usually within a certain time

called also median lethal dose

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