Elucidation: An immaterial entity that is of zero, one, or two dimensions and does not include a spatial region as part. Intuitively, a continuant fiat boundary is a boundary of some material entity that exists exactly where that object meets its surroundings. 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_0000140