The Collaborative International Dictionary of English v.0.48:

coupled \coupled\ adj.
   1. joined together especially in a pair or pairs.

   Syn: conjugate, conjugated.
        [WordNet 1.5]

   2. connected by a physical link, as railway cars or trailer
      trucks. Opposite of unconnected or unlinked

   Syn: joined, linked.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Couple \Cou"ple\, v. t. [imp. & p. p. Coupled (k[u^]p"'ld); p.
   pr. & vb. n. Coupling (k[u^]p"l[i^]ng).] [F. coupler, fr.
   L. copulare. See Couple, n., and cf. Copulate, Cobble,
   v.]
   [1913 Webster]
   1. To link or tie, as one thing to another; to connect or
      fasten together; to join.
      [1913 Webster]

            Huntsman, I charge thee, tender well my hounds, . .
            .
            And couple Clowder with the deep-mouthed brach.
                                                  --Shak.
      [1913 Webster]

   2. To join in wedlock; to marry. [Colloq.]
      [1913 Webster]

            A parson who couples all our beggars. --Swift.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coupled
    adj 1: joined together especially in a pair or pairs [syn:
           conjugate, conjugated, coupled]
    2: connected by a link, as railway cars or trailer trucks [syn:
       coupled, joined, linked]