Rhonchi are coarse rattling respiratory sounds, usually caused by secretions in bronchial airways. "Rhonchi" is the plural form of the singular word "rhonchus". Since the mid-1990s, it has no longer been considered appropriate terminology in auscultation of the thorax, as much confusion has been reported in the published literature which confuses this with crepitations and wheezes, so the exact nature of this term is unclear (see Fleischner Society for standardized terminology).
Similarly, rales are no longer used in much of Europe, North America, and Australia with regard to description of auscultatory findings. More appropriate terms for auscultation of the thorax are respiratory sounds and adventitious sounds (wheezes, crackles, pleural rubs). These have variably been associated with low-pitched, continuous sounds that are similar to wheezes or crackles. Other terminology for sounds that may be auscultated in the thorax include pulmonary murmurs, egophony, whispering pectoriloquy, and vocal fremitus. Also, percussion is often used to assess diseases of the chest.