The Collaborative International Dictionary of English v.0.48:

Syndetic \Syn*det"ic\, Syndetical \Syn*det"ic*al\, a. [Gr. ?,
   from ? to bind together; sy`n with + ? to bind; cf.
   Asyndetic.]
   Connecting; conjunctive; as, syndetic words or connectives;
   syndetic references in a dictionary. -- Syn*det"ic*al*ly,
   adv.
   [1913 Webster]

         With the syndetic juxtaposition of distinct members,
         the article is not often repeated.       --C. J. Grece
                                                  (Trans.
                                                  Maetzner's
                                                  Gram.).
   [1913 Webster]

WordNet (r) 3.0 (2006):

syndetic
    adj 1: connected by a conjunction [ant: asyndetic]