certifyv. t.[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.()We certify the king, that . . . thou shalt have no portion on this side the river. (Ezra iv. 16.)2. To give certain information of; to make certain, as a fact; to verify.(Hammond.)The industry of science at once certifies and greatly extends our knowledge of the vastness of the creation. (I. Taylor.)3. To testify to in writing; to make a declaration concerning, in writing, under hand, or hand and seal.()The judges shall certify their opinion to the chancellor, and upon such certificate the decree is usually founded. (Blackstone.)Certified check, A bank check, the validity of which is certified by the bank on which it is drawn.()