Elucidation: An independent continuant that has some portion of matter as part, is spatially extended in three dimensions, and that continues to exist through some interval of time, however short. Three principal subtypes of material entity are object, fiat object part, and object aggregate. 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_0000040