What is the natural or assigned action of any power or faculty, as of the soul, or of the intellect; the exertion of an energy of some determinate kind. As the mind opens, and its functions spread. Pope called?

function — The natural or assigned action of any power or faculty, as of the soul, or of the intellect; the exertion of an energy of some determinate kind. As the mind opens, and its functions spread. Pope. (Webster's 1913.)