WordNet (r) 3.0 (2006):

hookup
    n 1: a device providing a connection between a power source and
         a user; "some campsites have electrical hookups for
         trailers"
    2: a system of components assembled together for a particular
       purpose [syn: hookup, assemblage]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "hookup":
   Anschluss, addition, affiliation, agglomeration, agglutination,
   aggregation, agreement, alignment, alliance, amalgamation,
   articulation, assimilation, association, blend, blending, bond,
   bracketing, cabal, cahoots, cartel, centralization, circuit,
   clustering, coadunation, coalescence, coalition,
   coast-to-coast hookup, colleagueship, collegialism, collegiality,
   combination, combine, combo, communication, composition,
   comradeship, concatenation, concourse, concurrence, confederacy,
   confederation, confluence, confraternity, congeries,
   conglomeration, conjugation, conjunction, connection,
   consolidation, conspiracy, convergence, copartnership, copartnery,
   copulation, coupling, ecumenism, embodiment, encompassment, enosis,
   federalization, federation, fellowship, fraternalism, fraternity,
   fraternization, freemasonry, fusion, gathering, inclusion,
   incorporation, integration, intercommunication, intercourse,
   interlinking, joinder, joining, jointure, junction, junta,
   knotting, league, liaison, linkage, linking, marriage, meeting,
   meld, melding, merger, merging, net, network, package,
   package deal, pairing, partnership, radio links, sodality,
   solidification, sorority, splice, symbiosis, syncretism,
   syndication, syneresis, synthesis, tie, tie-in, tie-up,
   togetherness, unification, union, wedding, yoking