transmissometer

[ trans-muh-som-i-ter, tranz- ]
/ ˌtræns məˈsɒm ɪ tər, ˌtrænz- /

noun Meteorology.

an instrument for measuring visibility or the transmission of light in the atmosphere.
Also called hazemeter, transmittance meter.

Origin of transmissometer

First recorded in 1930–35; transmiss(ion) + -o- + -meter