Anatomical structure that has as its parts two or more portions of tissue of at least two different types and which through specific morphogenetic processes forms a single distinct structural unit demarcated by bona-fide boundaries from other distinct structural units of different types. [ http://orcid.org/0000-0001-9114-8737 http://purl.obolibrary.org/obo/CARO_0000055 ]