a period marked by distinctive character or reckoned from a fixed point or event
source: WordNet 3.0
a major division of geological time; an era is usually divided into two or more periods
source: WordNet 3.0
(baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched
source: WordNet 3.0
A fixed point of time, usually an epoch, from which a series of years is reckoned.
