British versus American spelling: palaeontology versus paleontology

Ontology, derived from the Greek words onto- for existence or being and -logy for study or interest, is the branch of metaphysics dealing with the nature of being [1]. The prefix palaeo-, or paleo- in the USA, comes from Greek palaios, meaning ancient. Therefore, palaeontology or paleontology is concerned with ancient beings or organisms: fossil animals and plants. Palaeontology is considered (and should be) a science! It uses scientific methods, relying on physics, chemistry, biology and geology, to study prehistoric life. Based on fossils and facts found, sometimes however, far-reaching conclusions are derived that introduce a metaphysical flavor to this branch of natural science— whether spelled palaeontology or paleontology.

Reference
[1] Michael Quinion: OLOGIES AND ISMS • Word Beginnings and Endings. Oxford University Press, Oxford and New York, 2002.