part of is part of part of bearer of has characteristic bounding layer of A relationship that applies between a continuant and its outer, bounding layer. Examples include the relationship between a multicellular organism and its integument, between an animal cell and its plasma membrane, and between a membrane bound organelle and its outer/bounding membrane. X outer_layer_of Y iff: . X :continuant that bearer_of some PATO:laminar . X part_of Y . exists Z :surface . X has_boundary Z . Z boundary_of Y has_boundary: http://purl.obolibrary.org/obo/RO_0002002 boundary_of: http://purl.obolibrary.org/obo/RO_0002000 material entity material entity laminar