What is meant by dating rocks relatively rather than absolutely?

Related questions

• What is the principle of Uniformitarianism and how is it important to the relative dating of rocks?
• What is the age of inclusions found in a rock relative to the rock in which they are found?
• What is the principle of cross-cutting relations and why is it important for relative dating?
• What forces can disturb relative dating?
• What is the law of superposition and how can it be used to relatively date rocks?
• How can fossils be used to determine the relative ages of rock layers?
• How does the law of crosscutting relationships help scientists determine the relative age of rocks?
• Are only sedimentary rocks used for relative age determination? Why?
• How do index fossils help determine age of rock layers?
• How do index fossils help determine age of rock layers?