insecticide

Etymology

It is formed from English insect + -cide,^[2][3][4][5] with the linking vowel -i-,^[6] and Merriam-Webster Unabridged treats it as International Scientific Vocabulary.^[7] The first part is from Latin insectum, literally "cut into",^[3][5] from in- (“into”) and secō (“to cut”).^[3] The ending is from French -cide and its source Latin -cīda (“cutter, killer”),^[2][3] from caedō (“to cut, kill”).^[2][3] The OED treats the agent and the act separately, the act having -cīdium (“a cutting, a killing”) behind its ending.^[2]

Earliest recorded meaning

The killing of insects: 14 October 1865, in the Saturday Review.^[2] The same paper has the attributive use, figuratively, in November 1865,^[2] and Etymonline, Merriam-Webster and the OED agree on 1865–66 for the word's main use.^[3][8][2] Etymonline also reports it earlier, in 1856, as a type of machine.^[3]

Semantic evolution

The first record is of the killing itself, a sense Etymonline calls humorous.^[3][2] The OED's first quotation for the agent is from 24 March 1866, in the Saturday Review again; its definition covers a person or a thing that kills insects, and specifically a preparation for destroying them.^[2][4] The killing sense is now rare.^[4] Etymonline dates the adjective insecticidal to 1857, before the noun.^[3]

Timeline

• 1865 – the killing of insects.^[2][4]
• 1865 – attributive, having the property of killing insects, here figuratively.^[2]
• 1866 – a person or thing that kills insects, especially a preparation for doing so.^[2][3] Merriam-Webster dates this sense to 1865.^[8][7]

Meanings

Noun

1. A substance used to kill insects and other arthropods: The orchard was sprayed with insecticide in early spring.^{[9][10][7][2]}
2. More broadly, an agent that harms or repels insects.^[7]
3. (rare) The killing of insects.^[4][7][2]

Adjective

1. Able to kill insects; insecticidal.^[2][4]

Word family

• insecticidal
• insecticidally

Related words

• insect
• -cide
• larvicide
• homicide

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g h i j Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
6. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
7. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ a b Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
9. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
10. ^ Collins English Dictionary (2023), Glasgow: HarperCollins