Emily Dickinson Lexicon

PHYS-I-OL'O-GY, n. [Gr. φυσιολογια; φυσις, nature, and λεγω, to discourse.]

1. According to the Greek, this word signifies a discourse or treatise of nature, but the moderns use the word in a more limited sense, for the science of the functions of all the different parts or organs of animals and plants, or, in other words, the offices which they perform in the economy of the individual.
2. The science of the mind, of its various phenomena, affections and powers. – Brown.