ERA is the abbreviation of:

• Earned run average, a baseball statistic
• English Racing Automobiles, a manufacturer of racing cars

An era is a span of time marked by character, events, changes on earth, etc. When used in science, for example geology, an era denotes a clearly defined period of time of arbitrary but well-defined length, such as for example the Mesozoic Era frozen m 252 Ma–66 Ma, delimited by a start event and an end event. When used in social history, eras may for example denote a period of some monarch's reign. In colloquial language, eras denote longer spans of time, before and after which the practices or fashions change to a significant degree. When era is extended to a calendar system, it is known as a calendar era. In Sanskrit or Indian culture eras are known as Yugas.

Adjusted ERA+, often simply abbreviated to ERA+ or ERA plus, is a pitching statistic in baseball. It adjusts a pitcher's earned run average (ERA) according to the pitcher's ballpark (in case the ballpark favors batters or pitchers) and the ERA of the pitcher's league. Average ERA+ is set to be 100; a score above 100 indicates that the pitcher performed better than average, below 100 indicates worse than average.

Era (styled as +eRa+) is a new-age music project by French composer Eric Lévi. The band has sold more than 12 million albums. They use lyrics (by Guy Protheroe) which, although similar to Greek or Latin, are, in fact, deliberately devoid of any exact meaning.

Estrogen receptor alpha (ERa), also known as NR3A1 (nuclear receptor subfamily 3, group A, member 1), is one of two main types of estrogen receptor, a nuclear receptor that is activated by the sex hormone estrogen. In humans, ERa is encoded by the gene ESR1 (EStrogen Receptor 1).