mayfly

American  

[may-flahy] / ˈmeɪˌflaɪ /

noun

• mayflies
  plural

1. Also called shadfly. any insect of the order Ephemeroptera, having delicate, membranous wings with the front pair much larger than the rear and having an aquatic larval stage and a terrestrial adult stage usually lasting less than two days.

2. Angling. Also May fly an artificial fly made to resemble this insect.

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mayfly British  

/ ˈmeɪˌflaɪ /

noun

1. Also called: dayfly. any insect of the order Ephemeroptera (or Ephemerida ). The short-lived adults, found near water, have long tail appendages and large transparent wings; the larvae are aquatic

2. angling an artificial fly resembling this

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Other Word Forms

Noun Inflected Forms

• mayflies
  plural

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Etymology

Origin of mayfly

First recorded in 1645–55; May + fly ¹

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Example Sentences

See Examples For:

mayfly mayflies

"In some cases we've got a 90% reduction in one particular mayfly species and also in one particular caddisfly, and a 30% reduction in two other mayfly species."

From BBC ● Mar. 10, 2026

Dead ahead: maybe 75 dancers, mostly in their late teens and early 20s, others in their 30s and 40s, sweating it out in this mayfly, once-every-five-weeks discothèque.

From Seattle Times ● Jan. 27, 2023

Many of these evanescent would-be Utopias, independent communes and mayfly principalities hardly did more than design a flag and choose a national anthem.

From Washington Post ● Jun. 22, 2021

The larvae of dozens of mayfly species populate healthy streams all year long and provide food for many animals, including fish.

From Scientific American ● Dec. 6, 2018

From the point of view of a mayfly, human beings are stolid, boring, almost entirely immovable, offering hardly a hint that they ever do anything.

From "Cosmos" by Carl Sagan

In addition, monitoring carried out before and after the restoration found an increase in river invertebrates, including mayflies and stoneflies.

From BBC ● Nov. 1, 2026

The plump mayflies known as green drakes were emerging on the water.

From The Wall Street Journal ● Jul. 5, 2026

Increased salinity usually spells trouble for freshwater insects like mayflies.

From Science Daily ● Oct. 6, 2023

The American Southeast has the greatest aquatic biodiversity of anywhere in the temperate world, with an amazing array of fish, mussels, aquatic snails, crawdads and aquatic insects, like mayflies and dragonflies.

From Seattle Times ● Oct. 21, 2022

Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their whole lives in the course of a single day.

From "Cosmos" by Carl Sagan

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