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

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

And the contemporary restaurant landscape brings its own challenges — ask any nascent restaurateur tempted by the siren song of Instagram walls or food trends with the lifespan of a mayfly — including the weight of online reviews. —Brock Keeling, Oc Register, 6 Apr. 2026

Each pseudo-scoop is as ephemeral as a mayfly. —David Remnick, New Yorker, 21 Mar. 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