1. A clinical sign in medicine characterized by a peculiar crackling, crinkly, or grating feeling or sound under the skin, around the lungs, or in the joints: "Crepitus is associated with gas gangrene, rubbing of bone fragments, air in the superficial tissues, or crackles of a consolidated area of the lungs in pneumonia."

"Crepitus in soft tissues is often a result of gas, most often air, that has penetrated and infiltrated an area where it should not normally be; as for example, the soft tissues beneath the skin (a condition called subcutaneous emphysema)."

2. Clicking sounds often heard in the movements of the bone joints; for example, in temporomandibular joints (of the lower jaw) resulting from joint irregularities: "Some crepituses conditions are caused by tissues rubbing together in abnormal ways."

"The most common causes of these types of crepituses are arthritides or joint injuries."

"Other common causes of crepituses exist when air gets inside soft tissues, which can cause crackling or popping sounds when pressed and the most important causes of these types of crepituses are holes in the airways or guts or anaerobic bacterial infections."

3. Flatulence or the noisy discharge of fetid gas discharged from the intestine: "This particular form of crepitus is considered to be a shorter version of crepitus ventris, "sound made by the belly".
4. Etymology: from the Latin crepitus, "a crackling sound" or "a rattle"; from Latin crepare. "to crack, to creak".