ephemera
/ɪˈfemərə/plural noun
1- things that exist or are used or enjoyed for only a short time生命短促的东西, 昙花一现的事物; 只供短时间使用（或享用）的东西。
1.1
- items of collectable memorabilia, typically written or printed ones, that were originally expected to have only short-term usefulness or popularity（尤指书写或印刷的、原来只指望暂时有用或流行的）值得收藏的纪念品：
Mickey Mouse ephemera.
米老鼠纪念品。
词源
late 16th cent.: plural of ephemeron, from Greek, neuter of ephēmeros 'lasting only a day'. As a singular noun the word originally denoted a plant said by ancient writers to last only one day, or an insect with a short lifespan, and hence was applied （late 18th cent.） to a person or thing of short-lived interest. Current use has been influenced by plurals such as trivia and memorabilia.