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

    A query result that contains occurrences, but does not contain any
    relationships between occurrences. These are produced by queries
    that do not involve relationship functions, or queries that do
    involve relationship functions but specify RESULT=NOSTRUCTURE,
    RESULT=BEGIN, or RESULT=END.