noun

1. a system of reckoning time by numbering the years from some important occurrence or given point of time the Christian Era
2. an event or date that marks the beginning of a new or important period in the history of something
3. a period of time measured from some important occurrence or date
4. a period of time considered in terms of noteworthy and characteristic events, developments, individuals, etc. an era of progress
5. Geol. a subdivision of an eon

Etymology: LL aera, era, earlier senses, “counters,” “items of account” < pl. of L aes (gen. aeris), copper: see ore

1. Baseball earned run average
   also era
2. Equal Rights Amendment