Preserved evidence of ancient life, including preserved skeletal or tissue material, molds or casts, and traces of behavior, such as fossilized footprints and burrows. Fossilization may alter biological material in a variety of ways, including permineralization, replacement, and compression.
Remains are often classified as fossils when they are older than 10,000 years, the traditional start of the Holocene (Recent) epoch. However, this date is only a practical guideline – scientists studying successions of plant or animal remains would not recognize any sudden change in the material at 10,000 years, and would typically refer to all material buried in sediments as fossil material.
The word fossil is derived from the Latin word fossilis, meaning “dug up.”