<unk>  refers to situations where noises are produced by the rubbing of parts one against the other, as in: * Crepitus, a crunching sensation felt in certain medical problems * Rales or crackles, abnormal sounds heard over the lungs with a stethoscope * A mechanism of sound production in grasshoppers during flight. Also called "wing snapping".
Crepitation
Eventration
Venous cutdown
Retching
Tincture
Crush injury
Denudation 
Clot retraction