1.
a significant period in history or in sb's life
2.
the beginning of a long period of history considered particularly significant
3.
[Geology]a unit of geological time that is a division of a period and is characterized by rock formation
4.
[Astronomy]a precise moment in time arbitrarily chosen as a reference point for defining the position of astronomical objects
1.
a significant period in history or in sb's life
2.
the beginning of a long period of history considered particularly significant
3.
[Geology]a unit of geological time that is a division of a period and is characterized by rock formation
4.
[Astronomy]a precise moment in time arbitrarily chosen as a reference point for defining the position of astronomical objects