Mediastinal lymphadenopathy or mediastinal adenopathy is an enlargement of the mediastinal lymph nodes.
the musical term for loud is F or forte and for soft P or piano.
The difference between a loud and a softer sound is the degree to which a medium is compressed and rarefied during the process by which the sound energy is put into the medium. Fortunately there is a question (and an answer) that goes into this in a bit of detail.