Very simply, relative age dating has to do with determining whether one geological or paleontological event happened before or after a second event. For example: Did rock layer A form before or after rock layer B? Did trilobites live before or after the dinosaurs?

What is a relative age dating?

Relative dating puts geologic events in chronological order without requiring that a specific numerical age be assigned to each event. This method uses the orientation of the Earths magnetic field, which has changed through time, to determine ages for fossils and rocks.