1. [v]  accept as valid, as of documents
2. [v]  approve or sanction officially

APPROBATE is a 9 letter word that starts with A.

1. \Ap"pro*bate\, a. [L. approbatus, p. p. of approbare
   to approve.]
   Approved. [Obs.] --Elyot.
   

2. \Ap"pro*bate\, v. t.
   To express approbation of; to approve; to sanction
   officially.
         I approbate the one, I reprobate the other. --Sir W.
                                                  Hamilton.
   Note: This word is obsolete in England, but is occasionally
         heard in the United States, chiefly in a technical
         sense for license; as, a person is approbated to
         preach; approbated to keep a public house. --Pickering
         (1816).