The Collaborative International Dictionary of English v.0.48:

Unanimous \U*nan"i*mous\ ([-u]*n[a^]n"[i^]*m[u^]s), a. [L.
   unanimus, unanimis; unus one + animus mind: cf. F. unanime.
   See Unit, and Animate.]
   1. Being of one mind; agreeing in opinion, design, or
      determination; consentient; not discordant or dissentient;
      harmonious; as, the assembly was unanimous; the members of
      the council were unanimous. "Both in one faith unanimous."
      --Milton.
      [1913 Webster]

   2. Formed with unanimity; indicating unanimity; having the
      agreement and consent of all; agreed upon without the
      opposition or contradiction of any; as, a unanimous
      opinion; a unanimous vote.
      [1913 Webster] -- U*nan"i*mous*ly, adv. --
      U*nan"i*mous*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

unanimously
    adv 1: of one mind; without dissent; "the Senate unanimously
           approved the bill"; "we voted unanimously" [syn:
           unanimously, nem con, nemine contradicente]