DOCBOOK: simple question about a choice of markup element

what's the appropriate inline markup to use for a term that is just
being introduced for the first time?  for example, "before you start
the procedure, you must first go out a buy a widget.  a widget is <insert
explanation here>..."                        ^^^^^^

  normally, such terms are shown in italics, and philosophically, i
don't think this should be an <emphasis> element.  and i don't see
any other tag that seems to fit here.  comments?

rday