The Collaborative International Dictionary of English v.0.48:
Angelology \An`gel*ol"o*gy\, n. [L. angelus, Gr. ? + -logy.] A discourse on angels, or a body of doctrines in regard to angels. [1913 Webster] The same mythology commanded the general consent; the same angelology, demonology. --Milman. [1913 Webster]WordNet (r) 3.0 (2006):
angelology n 1: the branch of theology that is concerned with angels