Eras

[eer-uh, er-uh] /ˈɪər ə, ˈɛr ə/

noun
1.
a period of time marked by distinctive character, events, etc.:
The use of steam for power marked the beginning of an era.
2.
the period of time to which anything belongs or is to be assigned:
She was born in the era of hansoms and gaslight.
3.
a system of chronologic notation reckoned from a given date:
The era of the Romans was based upon the time the city of Rome was founded.
4.
a point of time from which succeeding years are numbered, as at the beginning of a system of chronology:
Caesar died many years before our era.
5.
a date or an event forming the beginning of any distinctive period:
The year 1492 marks an era in world history.
6.
Geology. a major division of geologic time composed of a number of periods.
/ˈɪərə/
noun
1.
a period of time considered as being of a distinctive character; epoch
2.
an extended period of time the years of which are numbered from a fixed point or event: the Christian era
3.
a point in time, esp one beginning a new or distinctive period: the discovery of antibiotics marked an era in modern medicine
4.
(geology) a major division of geological time, divided into several periods: the Mesozoic era
/ˈiːrə/
noun acronym
1.
(in Britain) Education Reform Act: the 1988 act which established the key elements of the National Curriculum
2.
(in the US) Equal Rights Amendment: a proposed amendment to the US Constitution enshrining equality between the sexes
n.

1716, earlier aera (1610s), from Late Latin aera, era “an era or epoch from which time is reckoned,” probably identical with Latin aera “counters used for calculation,” plural of aes (genitive aeris) “brass, copper, money” (see ore, also cf. copper).

The Latin word’s use in chronology said to have begun in 5c. Spain (where, for some reason unknown to historians, the local era, aera Hispanica, began 38 B.C.E.; some say it was because of a tax levied that year). Like epoch, in English it originally meant “the starting point of an age;” meaning “system of chronological notation” is c.1640s; that of “historical period” is from 1741, e.g. the U.S. Era of Good Feeling (which was anything but) in reference to the Monroe Administration (1817-24), attested from 1817.
era
(îr’ə)
A division of geologic time, longer than a period and shorter than an eon.
1.
earned run average
2.
Economic Regulatory Administration
3.
Equal Rights Amendment
4.
exchange rate agreement