Abnormal respiratory sounds heard on auscultation of the chest, produced by passage of air through passages which contain secretion or exudate or which are constricted by spasm or a thickening of their walls; more usually referred to as crepitations or rhonchi (auscultation is the process of listening for sounds within the body by ear unassisted or using a stethoscope). Syn: Crackles, Râles