Noun

(en noun)

A particular period of history, especially one considered remarkable or noteworthy.

*{{quote-magazine, date=2012-01

, author=Donald Worster , title=A Drier and Hotter Future , volume=100, issue=1, page=70 , magazine= citation , passage=Phoenix and Lubbock are both caught in severe drought, and it is going to get much worse. We may see many such [dust] storms in the decades ahead, along with species extinctions, radical disturbance of ecosystems, and intensified social conflict over land and water. Welcome to the Anthropocene, the epoch when humans have become a major geological and climatic force.}}

A notable event which marks the beginning of such a period.

(astronomy) A precise instant of time that is used as a reference point.

(computing, uncountable) A precise instant of time that is used as a reference point (e.g. January 1, 1970, 00:00:00 UTC).

Noun

(en noun)

A stone milepost (or by extension in other materials), one of a series of numbered markers placed along a road at regular intervals, typically at the side of the road or in a median.

An important event in a person's life or career, in the history of a nation, in the life of some project, etc.

* {{quote-magazine, year=2012, month=March-April

, author= , title=Well-connected Brains , volume=100, issue=2, page=171 , magazine=(American Scientist) citation , passage=Creating a complete map of the human connectome would therefore be a monumental milestone but not the end of the journey to understanding how our brains work.}}