ephemeron

noun, plural e·phem·er·a [ih-fem-er-uh] /ɪˈfɛm ər ə/, e·phem·er·ons.

1. anything short-lived or ephemeral.
2. ephemera, items designed to be useful or important for only a short time, especially pamphlets, notices, tickets, etc.

noun plural -era (-ərə) or -erons

1. (usually plural) something transitory or short-lived