noun, plural e·phem·er·as, e·phem·er·ae [ih-fem–uh-ree] /ɪˈfɛm əˌri/ for 2.
- a plural of ephemeron.
- an ephemerid.
noun plural -eras or -erae (-əˌriː)
- a mayfly, esp one of the genus Ephemera
- something transitory or short-lived
- (functioning as plural) a class of collectable items not originally intended to last for more than a short time, such as tickets, posters, postcards, or labels
- a plural of ephemeron
late 14c., originally a medical term, from Medieval Latin ephemera (febris) “(fever) lasting a day,” from fem. of ephemerus, from Greek ephemeros “lasting only one day, short-lived,” from epi “on” (see epi-) + hemerai, dative of hemera “day,” from PIE *amer- “day.”
Sense extended 17c. to short-lived insects and flowers; general sense of “thing of transitory existence” is first attested 1751. Cf. Greek ephemeroi “men,” literally “creatures of a day.”