Give the definitions of psychology?

Some definitions of psychology are as under: William McDougall (1905) defined psychology as the "Science of Behaviour"
(B.F. Skinner) defined psychology as a "science of behaviour and experiences on human beings" According to Crow and Crow, "Psychology is the study of human behaviour and human relationship. "
According to Plato, "psychology is the science of the psyche or soul."
According to Aristotle, "Psychology is the science of living organisms."