ver·i·fi·er \-ˌfī(ə)r, -īə\noun (-s) 1.: one that searches for or discovers verification 2.: one that serves as verification < the problem of verifying beliefs … where the verifier lies beyond experience — J.W.Yolton > 3.: a machine used to check the correctness of the previous recording of data (as by punching cards or magnetizing tape)