era

(noun) a period marked by distinctive character or reckoned from a fixed point or event. Synonyms: epoch.

(noun) a major division of geological time; an era is usually divided into two or more periods. Synonyms: geological era.

(noun) (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. Synonyms: earned run average, ERA.