Transmissibility may have several meanings: In most contexts, transmissibility is related to permeability. In medicine, transmissibility is a synonym for basic reproduction number ...[vibration] Transmissibility is the ratio of output to input. Transmissibility (T) = output/input T>1 means amplification and maximum amplification occurs when forcing frequency (ff) and natural frequency (fn) of the system coincide. There is no unit designation for transmissibility, although it may sometimes be referred to as the `Q` facto...
• (n.) The quality of being transmissible.
The ability of a pathogen, like a virus, to spread from one person to another. 
The nondimensional ratio of the response amplitude of a system in steady-state forced vibration to the excitation amplitude. The ratio may be one of forces, displacements, velocities, or accelerations.