Elucidation: An entity that unfolds itself in time; the BFO category of occurrents comprises not only (1) the processes that unfold themselves in their successive temporal phases, but also (2) the boundaries or thresholds at the beginnings or ends of such temporal phases, as well as (3) the temporal and spatio-temporal regions in which these processes occur. Occurrent and continuant are the two highest categories (universals) in BFO. Source: Robert Arp, Barry Smith, and Andrew D. Spear: Building Ontologies with Basic Formal Ontology. The MIT Press Cambridge, Massachusetts London, England. ©2015 Massachusetts Institute of Technology. ISBN 978-0-262-52781-1, Glossary. https://www.ebi.ac.uk/ols4/ontologies/bfo/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FBFO_0000003