In concert hall acoustics, it's the opposite of reflection; the Sabin is a unit of it
ACOUSTICS OF ROOMS AND ENCLOSURES [PAR] Dec 1, 2000 ... Acoustical spaces such as concert halls, classrooms, churches, offices, etc ... As 
sound strikes a wall, some of it is reflected, while some is ....  sabine is 
calculated from measurements of sound decay .... properties of a room and its 
suitability for various uses.