- a particular period of time marked by distinctive features, events, etc.: The treaty ushered in an epoch of peace and good will.
- the beginning of a distinctive period in the history of anything: The splitting of the atom marked an epoch in scientific discovery.
- a point of time distinguished by a particular event or state of affairs; a memorable date: His coming of age was an epoch in his life.
- any of several divisions of a geologic period during which a geologic series is formed.
- Astronomy.
- an arbitrarily fixed instant of time or date, usually the beginning of a century or half century, used as a reference in giving the elements of a planetary orbit or the like.
- the mean longitude of a planet as seen from the sun at such an instant or date.
- the displacement from zero at zero time of a body undergoing simple harmonic motion.
- a point in time beginning a new or distinctive period
- a long period of time marked by some predominant or typical characteristic; era
- a precise date to which information, such as coordinates, relating to a celestial body is referred
- a unit of geological time within a period during which a series of rocks is formed
- the displacement of an oscillating or vibrating body at zero time
