1. 时代；年代；时期
You can refer to a period of history or a long period of time as an era when you want to draw attention to a particular feature or quality that it has.
e.g. ...the nuclear era...
核时代
e.g. ...the Reagan-Bush era...
里根-布什时期
名词新时期；纪元；年代；新时代网络防御率(EarnedRunAverage)；反应装甲(explosivereactivearmor)