Physiology
early 17th century: from Latin physiologia (perhaps via French), from Greek phusiologia ‘natural philosophy’ (see physio-, -logy).
wiktionary
From French physiologie, from Latin physiologia, from Ancient Greek φυσιολογία(phusiología, “natural philosophy”), from φύσις(phúsis, “nature”) + λόγος(lógos, “word”). Equivalent to physi- + -ology.
etymonline
physiology (n.)
1560s, "study and description of natural objects, natural philosophy" (a sense now obsolete), from French physiologie (16c.) or directly from Latin physiologia "natural science, study of nature," from Greek physiologia "natural science, inquiry into nature," from physios "nature" (see physio-) + logia "study" (see -logy). Meaning "science of the normal function of living things" is attested from 1610s. Related: Physiologic; physiologist.
The two words [physics/physiology] had once the same wide meaning of natural science or natural philosophy. They have now been narrowed & differentiated, physics retaining only the properties of matter & energy in inorganic nature, & physiology only the normal functions & phenomena of living beings. [Fowler, 1926]
