Entry 1 sense Webster, 1913 lemmatization /(lĕm`mȧ*tĭz*ā"shŭn)/ · lem·ma·tiz·a·tion · IPA 01 v. t. The act or process of lemmatizing; conversion into a lemma{2}. 1. The act or process of lemmatizing; conversion into a lemma{2}.