radioactive age

https://doi.org/10.1351/goldbook.R05078
The time, estimated from measurement of the isotopic composition, during which the content of a
radioactive
species within an object has remained unchanged except for
nuclear decay
.
Source:
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1549 [Terms] [Paper]