VMS Help SCA, SCA Topics, Glossary, structured_relationship_expression  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    A query that uses a relationship function (such as CONTAINED_
    BY, CALLED_BY, or TYPED) which asks for structure information.
    Structure information shows the relationships between occurrences
    found as well as the occurrences found. Structure information is
    provided by default.