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paraquat

American  
[par-uh-kwaht] / ˈpær əˌkwɑt /

noun

Chemistry.

  1. a toxic herbicide, C 1 2 H 1 4 N 2 ⋅2CH 3 SO 4 , applied to food and flower crops and to highway borders as a defoliant and weed-killer.

Paraquat British  
/ ˈpærəˌkwɒt /

noun

  1. a yellow extremely poisonous soluble solid used in solution as a weedkiller

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
paraquat Scientific  
/ păr′ə-kwŏt′ /

  1. A toxic compound used as a herbicide, especially in its colorless, dichloride form (C 12 H 14 Cl 2 N 2) or in its yellow, bismethyl sulfate form (C 14 H 20 N 2 O 8 S 2). Paraquat is used primarily to control grass and weeds. Its use in the United States is restricted because of its high level of toxicity.

Etymology

Origin of paraquat

1960–65; para- 1 + quat(ernary), in reference to the bond between the two pyridyl groups, which is in the para position with respect to their quaternary nitrogen atoms

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

“We paid thousands of dollars to have it analyzed. … I mean, the paraquat thing was totally scientifically wrong.”

From Slate • Dec. 23, 2025

The federal government banned the use of the weedkiller paraquat on golf courses in 2021.

From The Wall Street Journal • Oct. 31, 2025

Assembly Bill 1963 — a bill seeking to ban the use of paraquat in California — is working its way through the state Legislature and will be heard by the Senate Appropriations committee in August.

From Los Angeles Times • Jul. 22, 2024

“We would like to stress that paraquat is safe when used as directed,” Das said.

From Los Angeles Times • Apr. 8, 2024

California is the nation’s top user of paraquat, spraying millions of pounds annually, she said.

From Los Angeles Times • Apr. 8, 2024

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.