Of God and His Creatures

This latter process, in which the phantasm is called up at the beck of the already informed intellect, is what Wordsworth calls "imagination," and the faculty of accomplishing this process is the faculty of "imagination," a faculty intellectual rather than one of sense, because it means intellect leading and phantasy serving. Therefore the Aristotelian phantasia (described in De anima, III, iii, 9 sq.), called by St Thomas imaginatio, I have chosen to render by the old word phantasy. It is a faculty of the sentient nature, and therefore not imagination in the Wordsworthian sense. The word fancy has other meanings, inappropriate in this connexion.

Of God and His Creatures: 2.73