Wood horn

https://doi.org/10.1351/goldbook.W06681
A mechanical device that acts by absorption as a perfect photon trap.
Source:
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2284 (https://doi.org/10.1351/pac199668122223)