Nephelodometer

Neph`e`lo`dom´e`ter

    (nĕf`ė`lô`dǒm´ė`tẽr)

n.

1.

(Meteorol.) An instrument for reckoning the distances or velocities of clouds.

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.