cymometer

from The Collaborative International Dictionary of English v.0.48
Cymometer \Cy*mom"e*ter\, n. [Gr. ? wave -meter.]
   An instrument for exhibiting and measuring wave motion;
   specif. (Elec.), an instrument for determining the frequency
   of electic wave oscillations, esp. in connection with
   wireless telegraphy.
   [Webster 1913 Suppl.]
    

[email protected]