'Ephemeron' definitions:

Definition of 'ephemeron'

(from WordNet)
noun
Anything short-lived, as an insect that lives only for a day in its winged form [syn: ephemeron, ephemeral]

Definition of 'Ephemeron'

From: GCIDE
  • Ephemeron \E*phem"e*ron\, n.; pl. Ephemera. [NL. See Ephemera.] (Zo["o]l.) One of the ephemeral flies. [1913 Webster]