PERIOD


Meaning of PERIOD in English

n.

In geology, the basic unit of the geologic time scale.

During these spans of time, specific systems of rocks were formed. Originally, the method for defining the sequence of periods was relative; it was based on stratigraphy and paleontology . Carbon-14 dating and similar methods are now used to determine absolute ages for various periods.

Britannica Concise Encyclopedia.      Краткая энциклопедия Британика.