Source : Webster's Revised Unabridged Dictionary (1913)

Thermometrograph \Ther`mo*met"ro*graph\, n. [Thermo- + Gr. ?
   measure + -graph.] (Physics)
   An instrument for recording graphically the variations of
   temperature, or the indications of a thermometer.

Source : WordNet®

thermometrograph
     n : a thermometer that records temperature variations on a graph
         as a function of time [syn: {thermograph}]