A dinosaur fossil is the preserved remains or traces of dinosaurs that lived millions of years ago. These fossils can include bones, teeth, footprints, and even eggs. They provide valuable information about the size, shape, and behavior of these ancient creatures, helping scientists understand how dinosaurs lived and evolved. Fossils are typically found in sedimentary rock, formed from layers of mud and sand that buried the remains over time. Paleontologists, scientists who study fossils, use various techniques to excavate and analyze these specimens. The study of dinosaur fossils contributes to our knowledge of Earth's history and the development of life on our planet.