physiology (n.)
1560s, "study and description of natural objects," from Middle French physiologie or directly from Latin physiologia "natural science, study of nature," from Greek physiologia "natural science, inquiry into nature," from physio- "nature" (see physio-) + logia "study" (see -logy). Meaning "science of the normal function of living things" is attested from 1610s. Related: Physiologic; physiologist.