"The study of the nature of ignorance or of what it is impossible to know; a particular theory concerning this", Mid 19th cent.; earliest use found in James Frederick Ferrier (1808–1864), philosopher. From ancient Greek ἄγνοια ignorance (probably from ἀγνοεῖν to be ignorant + -ία) + -ology.[agnoiology etymology, agnoiology origin, 英语词源]