from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See mayfly.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mayfly.
from the GNU version of the Collaborative International Dictionary of English
- n. A neuropterous insect of the genus Ephemera and related genera, of many species, and inhabiting fresh water in the larval state; the ephemeral fly; -- so called because it commonly lives but one day in the winged or adult state. See Ephemeral fly, under ephemeral.
from The Century Dictionary and Cyclopedia
- n. A May-fly: a popular name of the neuropterous insects of the family Ephemeridæ: so called because, however long they may live in the larval state, in their perfect form they exist only from a few hours to a few days, taking no food, but only propagating and then dying. See Ephemeridæ.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. slender insect with delicate membranous wings having an aquatic larval stage and terrestrial adult stage usually lasting less than two days
day + fly, since the adults typically live only for a day. (Wiktionary)