The Collaborative International Dictionary of English v.0.48:

redemption \re*demp"tion\ (r[-e]*d[e^]mp"sh[u^]n), n. [F.
   r['e]demption, L. redemptio. See redeem, and cf. ransom.]
   The act of redeeming, or the state of being redeemed;
   repurchase; ransom; release; rescue; deliverance; as, the
   redemption of prisoners taken in war; the redemption of a
   ship and cargo. Specifically:
   (a) (Law) The liberation of an estate from a mortgage, or the
       taking back of property mortgaged, upon performance of
       the terms or conditions on which it was conveyed; also,
       the right of redeeming and reentering upon an estate
       mortgaged. See Equity of redemption, under Equity.
   (b) (Com.) Performance of the obligation stated in a note,
       bill, bond, or other evidence of debt, by making payment
       to the holder.
   (c) (Theol.) The procuring of God's favor by the sufferings
       and death of Christ; the ransom or deliverance of sinners
       from the bondage of sin and the penalties of God's
       violated law.
       [1913 Webster]

             In whom we have redemption through his blood.
                                                  --Eph. i. 7.
       [1913 Webster]

WordNet (r) 3.0 (2006):

redemption
    n 1: (theology) the act of delivering from sin or saving from
         evil [syn: redemption, salvation]
    2: repayment of the principal amount of a debt or security at or
       before maturity (as when a corporation repurchases its own
       stock)
    3: the act of purchasing back something previously sold [syn:
       redemption, repurchase, buyback]

The Devil's Dictionary (1881-1906):

REDEMPTION, n.  Deliverance of sinners from the penalty of their sin,
through their murder of the deity against whom they sinned.  The
doctrine of Redemption is the fundamental mystery of our holy
religion, and whoso believeth in it shall not perish, but have
everlasting life in which to try to understand it.

    We must awake Man's spirit from his sin,
        And take some special measure for redeeming it;
    Though hard indeed the task to get it in
        Among the angels any way but teaming it,
        Or purify it otherwise than steaming it.
    I'm awkward at Redemption -- a beginner:
    My method is to crucify the sinner.
                                                           Golgo Brone