The primary difference is that absolute dating assigns an actual time or age to an event or object.
Relative dating simply says one is older than the other but no age is specified.
Short Answer: The term relative dating is distinguished from absolute dating to make it clear that one does not get a specific estimate of the age of an object from relative dating, but one does get such an estimate of true age from absolute dating.
There are several techniques employed in both sets of methods. Long Answer: Sciences such as geology, paleontology and archeology are very interested in identifying the age of objects found and these scientists sometimes use both relative dating or absolute dating to characterize the age of the objects they study.
Archeology is the scientific study of past human culture and behavior, from the origins of humans to the present.
Archaeology studies past human behavior through the examination of material remains of previous human societies.
Very often historical evidence is found in layers and older layers are further down that the top layers.
For example: If an archaeologist is studying past civilizations, the archaeologist may be able to say that in a particular location the ruins of one civilization were found to have been built on another and so the layers unearthed in an excavation convey the sequence of historical occupations without revealing the actual dates.
However, archaeology is distinct from paleontology and studies only past human life.
The difference between relative dating and absolute dating is that relative dating is a method of sequencing events in the order in which they happened.
Absolute dating is a method of estimating the age of a rock sample in years via radiometric techniques.
The table below tracks the decay, half-life by half-life, of a radioactive isotope, and the accumulation of the daughter product isotope that the parent changes into once it decays. There are several different radioactive isotope systems that are used for measuring ages of geologic materials.
For more information on these systems, see the isotopes and half-lives section of the Geologic Time Basics page.