| Term | Definition |
| absolute dating | determine age of rocks using radioactive dating |
| relative dating | determining whether it is older or younger than it's surroundings, no numbers |
| radiometric dating | daughter and parent product process |
| radioactive decay | process in which the radioactive isotopes break down |
| fault | a break in a body of rock along which one block sides are relative to another |
| folding | internal force due to stress which bends the surface |
| tilting | occurs when internal forces in the Earth slant rock layers |
| angular unconformity | between horizontal rock layers and rock layers that are tiltled |
| non-conformity | all rocks except sedimentary rocks are eroded |
| unconformity | one or more missing layers in a sequence, gap in geologic record |
| disconformity | an ersinal surface between horizontal layers of sedimentary rocks |
| superposition | principle that states that younger layers are on top and the older ones are on bottom, Steno's Law |
| catastrophism | a principle that states that geologic change occurs suddenly |
| uniformitarianism | states that the Earth's processes occurring today are similar to those that occurred in the past |