palaios + ontos + logos

Greek palaios meant ancient or old, ontos was the genitive of on meaning being or existence, and logos meant study or discourse. Palaeontologie appeared in the French scientific literature in 1822, coined by Henri Ducrotay de Blainville in Paris, to describe the study of ancient living beings through their fossil remains. The field had existed without a name: Georges Cuvier had been reconstructing extinct mammals from bones since the 1790s, but Blainville gave the practice a scientific designation.

The concept of extinction itself was contested when paleontology was named. Thomas Jefferson, a diligent naturalist, refused to believe species could go extinct — God would not permit it. He asked Lewis and Clark to watch for mammoths during their 1804 expedition. It was Cuvier's comparative anatomy of fossil bones, combined with living animals, that established beyond reasonable doubt that species did go extinct and had been doing so for millions of years.

Charles Lyell's Principles of Geology, published in three volumes between 1830 and 1833, provided the temporal framework paleontology needed: the earth was millions of years old, not thousands. With deep time established, fossils could be read as a chronological record. Paleontology became the science of reading that record.

Today paleontology encompasses microfossils, molecular paleontology, and paleoclimatology. Fossilized pollen grains map ancient climates. Ancient DNA extracted from permafrost recovers genomes of long-dead species. The Greek palaios — old — now reaches back billions of years to the earliest traces of life on Earth.