predictor
     n 1: someone who makes predictions of the future (usually on the
          basis of special knowledge) [syn: {forecaster}, {prognosticator},
           {soothsayer}]
     2: information that supports a probabilistic estimate of future
        events; "the weekly bulletin contains several predictors
        of mutual fund performance"
     3: a computer for controlling antiaircraft fire that computes
        the position of an aircraft at the instant of a shell's
        arrival
Source: WordNet® 2.0