plural mosquitoes also mosquitos
: any of a family (Culicidae) of dipteran flies with females that have a set of slender organs in the proboscis adapted to puncture the skin of animals and to suck their blood and that are in some cases vectors of serious diseases

Illustration of mosquito

Illustration of mosquito

Examples of mosquito in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
On a scale for itchiness, my Eichenprozessionsspinner rash would outrank all the mosquitoes, spiders, fleas, and midges that had ever bitten into my flesh. Ben Crair, New Yorker, 31 July 2026 Last month, Alameda County stepped up mosquito abatement by spraying insecticide in Newark after five birds tested positive for West Nile virus there. Grant Stringer, Mercury News, 29 July 2026 The Health Department also lays traps to collect mosquitoes to test them for the virus. Felicity Abbott, CBS News, 29 July 2026 In the 1960s a contagious reticulum cell sarcoma spread through a colony of laboratory hamsters, passing from animal to animal and even by the bite of a mosquito. John Drake, Forbes.com, 27 July 2026 See All Example Sentences for mosquito

Word History

Etymology

Spanish, diminutive of mosca fly, from Latin musca — more at midge

First Known Use

1572, in the meaning defined above

Time Traveler
The first known use of mosquito was in 1572

Browse Nearby Words

Cite this Entry

“Mosquito.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mosquito. Accessed 1 Aug. 2026.

Kids Definition

mosquito

noun
plural mosquitoes also mosquitos
: any of numerous two-winged flies of which the females have a needlelike structure of the mouth region adapted to puncture the skin and suck the blood of animals
Etymology

from Spanish mosquito "mosquito," literally "little fly," from mosca "fly"

Medical Definition

plural mosquitoes also mosquitos
: any of numerous dipteran flies of the family Culicidae that have a rather narrow abdomen, usually a long slender rigid proboscis, and narrow wings with a fringe of scales on the margin and usually on each side of the wing veins, that have in the male broad feathery antennae and mouthparts not fitted for piercing and in the female slender antennae and a set of needlelike organs in the proboscis with which they puncture the skin of animals to suck the blood, that lay their eggs on the surface of stagnant water, that include many species which pass through several generations in the course of a year and hibernate as adults or winter in the egg state, and that include some species which are the only vectors of certain diseases see aedes, anopheles, culex

More from Merriam-Webster on mosquito

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster