Final answer:
Rhonchus is a medical term of Greek origin meaning 'snoring,' used to describe coarse rattling sounds in the respiratory airways. It is usually associated with airway obstruction due to conditions like bronchitis. The spelling 'rh' from rhonchus is one of the least common ways to spell the sound [r].
Step-by-step explanation:
The term rhonchus is derived from the Greek word meaning snoring. It is a medical term used to describe the coarse rattling respiratory sounds, somewhat similar to snoring, that are usually caused by obstructions to the air flow in the respiratory airways. Rhonchus can indicate the presence of conditions such as bronchitis or respiratory infections, where mucus and other material can partially obstruct air movement.
Comparatively, in the word rhinoceros, the first element rhino, in Greek means nose, and the second element ceros, means horn. So rhinoceros simply means the animal with a horn on its nose. Similarly, the term rhonchus relates to breathing sounds that could be analogized to snoring.
Of the given ways to spell [r], <r> is the most common, followed by <rr>. The least common are <wr> and <rh>.