D defs.my
Entry 1 sense Webster, 1913

Dayfly

/(dā"flī`)/ · Day·fly · IPA
01 n. A neuropterous insect of the genus Ephemera and related genera, of many species, and inhabiting fresh water in the larval state; the epheme…
  1. 1.
    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.(Zool.) [Outdated] See: Ephemeral