par·​a·​sit·​ism | \ ˈper-ə-sə-ˌti-zəm How to pronounce parasitism (audio) , -ˌsī-, ˈpa-rə- \

Definition of parasitism

1 : the behavior of a parasite
2 : an intimate association between organisms of two or more kinds especially : one in which a parasite obtains benefits from a host which it usually injures

Examples of parasitism in a Sentence

Recent Examples on the Web Yet despite their parasitism, mistletoes may well be the Robin Hoods of plants. Rachel Ehrenberg, Smithsonian Magazine, "The Biology of Mistletoe," 23 Dec. 2020 Other types of symbiosis include parasitism, commensalism, and amensalism. Liz Langley, National Geographic, "We couldn't have figs without wasps. Here's how mutualism works.," 25 Sep. 2020 The one-two punch of fire suppression and cowbird parasitism drove Kirtland's numbers down. Jason Daley, Smithsonian, "North America’s Rarest Warbler Comes Off the Endangered List," 11 Oct. 2019 Open enrollment parasitism must be addressed at the state level. Bob Dohr, Milwaukee Journal Sentinel, "Eight candidates are running for a seat on the Palmyra-Eagle school board. Here are their plans for the district.," 29 Jan. 2020 So a team of entomologists led by Refugio Lomeli-Flores set out to conduct a survey of natural enemies of the bagrada bug, collecting its eggs in fields throughout Guanajuato to watch for signs of parasitism. Andrea Michelson, Smithsonian, "Tiny Parasitic Wasp Named After Idris Elba Hijacks Stink Bug Eggs," 21 Nov. 2019 In most cases, wasps target these pests through parasitism. Katherine J. Wu, Smithsonian, "Five Real Life Wasp Superpowers Not in Ant-Man and the Wasp," 22 Mar. 2018 The internet need not be characterized by predation and parasitism. Brendan Eichand, WSJ, "The Internet’s ‘Original Sin’ Endangers More Than Privacy," 27 Apr. 2018 Hauber studies a behavior known as brood parasitism, in which birds lay eggs in the nests of other species, leaving the unwitting foster parents to rear their chicks. Matt Warren, Science | AAAS, "Here’s what happens when you replace toads and turtles with 3D-printed replicas in the wild," 17 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'parasitism.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of parasitism

circa 1611, in the meaning defined at sense 1

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Time Traveler for parasitism

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The first known use of parasitism was circa 1611

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Cite this Entry

“Parasitism.” Dictionary, Merriam-Webster, Accessed 4 Mar. 2021.

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More Definitions for parasitism


par·​a·​sit·​ism | \ ˈpar-ə-sə-ˌtiz-əm How to pronounce parasitism (audio) , -ˌsīt-ˌiz- How to pronounce parasitism (audio) \

Medical Definition of parasitism

1 : an intimate association between organisms of two or more kinds especially : one in which a parasite obtains benefits from a host which it usually injures

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