Entry 1 sense Webster, 1913 epistemology /ĕp-ĭsˌ-təm-äl'-əj-ēˌ/ · e·pis·te·mol·o·gy · IPA /ɪˌpɪstəˈmɑləd͡ʒi/ 01 n. The theory or science of the method or grounds of knowledge. 1. The theory or science of the method or grounds of knowledge.