The Collaborative International Dictionary of English v.0.48:

Certificate \Cer*tif"i*cate\, n. [F. certificat, fr. LL.
   certificatus made certain, p. p. of certificare. See tify.]
   1. A written testimony to the truth of any fact; as,
      certificate of good behavior.
      [1913 Webster]

   2. A written declaration legally authenticated.
      [1913 Webster]

   Trial by certificate, a trial which the testimony of the
      person certifying is the only proper criterion of the
      point in dispute; as, when the issue is whether a person
      was absent in the army, this is tried by the certificate
      of the proper officer in writing, under his seal.
      --Blackstone.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Certificate \Cer*tif"i*cate\, v. t. [imp. & p. p.
   Certificated; p. pr. & vb. n. Certificating.] [See
   Certify.]
   [1913 Webster]
   1. To verify or vouch for by certificate.
      [1913 Webster]

   2. To furnish with a certificate; as, to certificate the
      captain of a vessel; a certificated teacher.
      [1913 Webster]

WordNet (r) 3.0 (2006):

certificate
    n 1: a document attesting to the truth of certain stated facts
         [syn: certificate, certification, credential,
         credentials]
    2: a formal declaration that documents a fact of relevance to
       finance and investment; the holder has a right to receive
       interest or dividends; "he held several valuable securities"
       [syn: security, certificate]
    v 1: present someone with a certificate
    2: authorize by certificate