Library /sys$common/syshlp/decw$dxmhelp_help.hlb Glossary, keyword  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  A keyword is a subject that is associated with one or
  more help topics. A help topic can have one or more
  keywords associated with it.

  You can use the Keyword... menu item of the Search menu
  to see the list of keywords and to see topics that have
  a specific keyword associated with them.