transmissometer
/ˌtrænzmɪˈsɑmɪtər/
noun
- An instrument that measures how much light or other radiation passes through a substance, such as air, water, or glass.
- The airport uses a transmissometer to measure visibility for pilots.
- A transmissometer helped the researchers check the clarity of the lake water.
- The technician calibrated the transmissometer before testing the new optical fiber.