Meaning

noun a period marked by distinctive character or reckoned from a fixed point or event

noun a major division of geological time; an era is usually divided into two or more periods

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

originEtymology tree Late Latin aerabor. English era Borrowed from Late Latin aera.

Etymology from Wiktionary, CC BY-SA 3.0