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: a hygroscopic corrosive liquid organophosphate C8H20O7P2 that is a powerful anticholinesterase and is used especially as an insecticide

Word History

Etymology

tetra- + ethyl + pyrophosphate

First Known Use

1948, in the meaning defined above

Time Traveler
The first known use of TEPP was in 1948

Browse Nearby Words

Cite this Entry

“TEPP.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/TEPP. Accessed 30 Nov. 2025.

Medical Definition

: a mobile hygroscopic corrosive liquid organophosphate C8H20O7P2 that is a powerful anticholinesterase and is used as an insecticide and parasympathomimetic agent

called also tetraethyl pyrophosphate

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