From The Collaborative International Dictionary of English v.0.48:
Confirmation \Con`fir*ma"tion\, n. [F. confirmation, L. confirmatio.] 1. The act of confirming or strengthening; the act of establishing, ratifying, or sanctioning; as, the confirmation of an appointment. [1913 Webster]
Their blood is shed In confirmation of the noblest claim. --Cowper. [1913 Webster]
2. That which confirms; that which gives new strength or assurance; as to a statement or belief; additional evidence; proof; convincing testimony. [1913 Webster]
Trifles light as air Are to the jealous confirmations strong As proofs of holy writ. --Shak. [1913 Webster]
3. (Eccl.) A rite supplemental to baptism, by which a person is admitted, through the laying on of the hands of a bishop, to the full privileges of the church, as in the Roman Catholic, the Episcopal Church, etc. [1913 Webster]
This ordinance is called confirmation, because they who duly receive it are confirmed or strengthened for the fulfillment of their Christian duties, by the grace therein bestowed upon them. --Hook. [1913 Webster]
4. (Law) A conveyance by which a voidable estate is made sure and not voidable, or by which a particular estate is increased; a contract, express or implied, by which a person makes that firm and binding which was before voidable. [1913 Webster]