Define relative age dating
For example, fission track dating measures the microscopic marks left in crystals by subatomic particles from decaying isotopes.
Another example is luminescence dating, which measures the energy from radioactive decay that is trapped inside nearby crystals.
In other words, we can say that the age in relative dating is ascertained by witnessing the layers of deposition or the rocks.
Others measure the subatomic particles that are emitted as an isotope decays.
Some measure the decay of isotopes more indirectly.
Relative Dating and Absolute Dating are two types of such techniques which are under practice to determine the age of the fossils, objects or civilizations.
The relative dating is the technique in the Geology through which the age is determined with relation to the other objects.