The Collaborative International Dictionary of English v.0.48:

Subordinate \Sub*or"di*nate\, v. t. [imp. & p. p.
   Subordinated; p. pr. & vb. n. Subordinating.]
   1. To place in a lower order or class; to make or consider as
      of less value or importance; as, to subordinate one
      creature to another.
      [1913 Webster]

   2. To make subject; to subject or subdue; as, to subordinate
      the passions to reason.
      [1913 Webster] -- Sub*or"di*nate*ly, adv. --
      Sub*or"di*nate*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

subordinating
    adj 1: serving to connect a subordinate clause to a main clause;
           "`when' in `I will come when I can' is a subordinating
           conjunction" [syn: subordinating(a), subordinative]
           [ant: coordinating(a), coordinative]