soffit
Pronunciation:
/ˈsɑ.fɪt//ˈsɒf.ɪt/noun
Definitions
The visible underside of an arch, balcony, beam, cornice, staircase, vault or any other architectural element.
(pipe technology) The top point of the inside open section of a pipe or box conduit.
Example: The elevation of the pipe soffit is 10.4 meters above mean sea level.