par·​a·​sit·​oid ˈper-ə-sə-ˌtȯid How to pronounce parasitoid (audio)
: an insect and especially a wasp that completes its larval development within the body of another insect eventually killing it and is free-living as an adult
parasitoid adjective

Examples of parasitoid in a Sentence

Recent Examples on the Web Conserve biological control agents such as predators and the parasitoids that feed on insect pests. oregonlive, 1 Apr. 2022 Whereas uninfected larvae succumbed to the parasites, the infected larvae—and their plasma—killed almost every parasite, aside from the basket-cocoon parasitoid M. pulchricornis. Mennatalla Ibrahim, Science | AAAS, 29 July 2021 The larvae of polyembryonic parasitoid wasps, which hatch from eggs that are laid on top of caterpillar eggs, occasionally develop into adults that are not just infertile but have a habit of eating other larvae. Tim Brinkhof, Discover Magazine, 9 Mar. 2021 Recently the researchers used bar coding to take a closer look at 16 species of parasitoid flies known to scientists for more than a century. Richard Conniff, Discover Magazine, 18 Nov. 2010 Sensory arsenal on the stinger of the parasitoid jewel wasp and its possible role in identifying cockroach brains. Seriously Science, Discover Magazine, 28 Oct. 2014 Like many parasitoid species, the emerald jewel wasp is a specialist with only one option for a host—in this case, the American cockroach, Periplaneta americana. Kenneth C. Catania, Scientific American, 1 Feb. 2021 Technically speaking, the alien is a parasitoid, an organism that, unlike most parasites, ultimately kills its host. Kenneth C. Catania, Scientific American, 1 Feb. 2021 Similarly, female parasitoid wasps will compete over the most desirable hosts in which to lay their eggs. Jennifer Ouellette, Ars Technica, 29 Oct. 2020 See More

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

Word History

First Known Use

1914, in the meaning defined above

Time Traveler
The first known use of parasitoid was in 1914

Dictionary Entries Near parasitoid

Cite this Entry

“Parasitoid.” Dictionary, Merriam-Webster, Accessed 23 Sep. 2023.

Medical Definition


1 of 2 adjective
par·​a·​sit·​oid ˈpar-ə-sə-ˌtȯid How to pronounce parasitoid (audio) -ˌsīt-ˌȯid How to pronounce parasitoid (audio)
: resembling a parasite
: being a parasitoid


2 of 2 noun
: an insect and especially a wasp that completes its larval development within the body of another insect which it eventually kills and that is free-living as an adult
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