The Free On-line Dictionary of Computing (30 December 2018):

domain handle

    Information held by a domain name registrar
   about a registrant (the person or organisation that owns the
   name).  Typically the registrar stores one copy of this
   information and refers to that copy for each additional domain
   registered by the same person.  The information would include
   basic contact details: name, e-mail address, etc. and billing
   information.  Some of this information would be used to
   populate the whois database entry for a domain.


(http://www.easyname.eu/support/domains/20-what-is-a-domain-handle).

   (2009-09-17)