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

Crappie like to hover below their prey, fining in place and examining slow-swimming invertebrates such as damselfly, dragonfly, and mayfly nymphs, as well as small leeches. —Cory Schmidt, Outdoor Life, 15 Apr. 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

Here, the summer evening breeze ripples through the willows, and the terrace resounds with sounds of trout rising to catch the mayfly. —Condé Nast, Condé Nast Traveler, 12 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