The Collaborative International Dictionary of English v.0.48:

Certify \Cer"ti*fy\, v. t. [imp. & p. p. Certified; p. pr. &
   vb. n. Certifying.] [F. certifier, LL. certificare; L.
   certus certain + facere to make. See Certain, and cf.
   Certificate, v. t.]
   1. To give cetain information to; to assure; to make certain.
      [1913 Webster]

            We certify the king, that . . . thou shalt have no
            portion on this side the river.       --Ezra iv. 16.
      [1913 Webster]

   2. To give certain information of; to make certain, as a
      fact; to verify. --Hammond.
      [1913 Webster]

            The industry of science at once certifies and
            greatly extends our knowledge of the vastness of the
            creation.                             --I. Taylor.
      [1913 Webster]

   3. To testify to in writing; to make a declaration
      concerning, in writing, under hand, or hand and seal.
      [1913 Webster]

            The judges shall certify their opinion to the
            chancellor, and upon such certificate the decree is
            usually founded.                      --Blackstone.
      [1913 Webster]

   Certified check, A bank check, the validity of which is
      certified by the bank on which it is drawn.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

certified check \certified check\ n.
   a check drawn on a bank and bearing marks from that bank
   guaranteeing that funds have been reserved for payment.
   [PJC]

WordNet (r) 3.0 (2006):

certified check
    n 1: a check containing certification that the person who issued
         the check has sufficient funds on deposit to cover payment
         [syn: certified check, certified cheque]