Homeostasis imbalance process ontology (HOIP) systematizes a wide variety of processes triggered by homeostatic imbalance. The version of HoiP focuses on COVID-19 infectious processes and cellular senescence. The HoIP contains an is-a hierarchy that is organized into three layers: the top layer contains general terms, mostly derived from the Basic Formal Ontology. The top layer also defines functioning-related processes. The intermediate layer contains biomedical terms in OBO foundry from VO, UBERON, Cell Ontology, NCBI Taxon, ChEBI, Gene Ontology, PATO, OGG, INOH, HINO, DOID, HP, Protein Ontology, Symptom Ontology, CIDO, BSPO, WBbt, WBIs, HuPSON, NCIT, and Relational ontology (RO). The lower layer contains homeostasis imbalance-dependent terms.Related article:Ontology for Cellular Senescence MechanismsYuki Yamagata, Tsubasa Fukuyama, Shuichi Onami, Hiroshi MasuyabioRxiv 2023.03.09.531883; doi: https://doi.org/10.1101/2023.03.09.531883severe COVID-19 course:http://purl.bioontology.org/ontology/HOIP/HOIP_0039222COVID-19 course associated with acute respiratory distress syndromehttp://purl.bioontology.org/ontology/HOIP/HOIP_0036006COVID-19 specific process.http://purl.bioontology.org/ontology/HOIP/HOIP_0037002Cellular senescence course:http://purl.bioontology.org/ontology/HOIP/HOIP_0060024Chronic cellular senescence coursehttp://purl.bioontology.org/ontology/HOIP/HOIP_0060195