mayfly

noun

may·​fly ˈmā-ˌflī 

: any of an order (Ephemeroptera) of insects with an aquatic nymph and a short-lived, fragile adult lacking mouthparts and having membranous, heavily veined wings and two or three long, threadlike tails

Note: the wings of the mayfly are held vertically above the body when closed.

called also ephemerid

Illustration of mayfly

Examples of mayfly in a Sentence

Recent Examples on the Web

While the lights themselves aren’t drawing in spiders, the moths, gnats, mosquitoes, and mayflies bobbing around the lights do. — Karen Brewer Grossman, Southern Living, 9 July 2026

The Minnesota Department of Transportation says an exploding population of mayflies could cause serious trouble for drivers in southeast Minnesota. — Frankie McLister, CBS News, 12 June 2026

To make the distinction, midges are often smaller and mayflies have a more upright wing posture, according to NexGreen. — Sarah Moore, Freep.com, 28 May 2026

Salmonflies, however, are bigger and clumsier than smaller insects like mayflies. — Dac Collins, Outdoor Life, 14 May 2026

Word History

First Known Use

circa 1653, in the meaning defined above

Kids Definition

mayfly

noun

may·​fly -ˌflī 

: any of a group of insects that as adults live only a short time and have fragile wings