Although a number of investigators have adopted the O'Carroll et al. (1996) nomenclature and applied it in their studies, and others have acknowledged its role in highlighting the need for clarification of terms, the nomenclature has not been widely used in the research and clinical communities. The rationale behind the rebuilding of the O'Carroll et al. nomenclature is to increase the ability of clinicians, epidemiologists, policy makers, and researchers to better communicate with each other and study similar populations at risk for suicide-related ideations, communications, and behaviors. This article presents a revised and refined version of the O'Carroll et al. (1996) nomenclature for suicidology, with a focus on suicide-related ideations, communications, and behaviors. The hope is that this refinement will result in the development of operational definitions and field testing of this nomenclature in clinical and research settings. This revision would not have been possible without the international collaboration and dialogue addressing the nomenclature of suicidology since the O'Carroll et al. nomenclature appeared in 1996. (Contains 4 tables and 4 figures.) [For Part 1, see EJ785863.]