alethiologyrare.|əˌliːθɪˈɒlədʒɪ| [f.Gr. ἀλήθεια truth + -ology.] The doctrine of truth, that part of logic which treats of truth. 1837–8Sir W. Hamilton Logic iv. 69 (L.) The first part [of logic] treats of the nature of truth and error, and of the highest laws for their discrimination, Alethiology.