Abstract Background Stem cells and stem cell lines are widely used in biomedical research. The Cell Ontology (CL) and Cell Line Ontology (CLO) are two community-based OBO Foundry ontologies in the domains of in vivo cells and in vitro cell line cells. respectively. Results To support standardized stem cell investigations. https://www.nacrack.com/flash-deal-Diamond-Painting-Zee-en-strand-special-find/