Stertor

Stertor (from Latin stertere 'to snore') is a term first used in 1804 to describe a noisy breathing sound, such as snoring. It is caused by partial obstruction of the upper airways, at the level of the nasopharynx or oropharynx.

It is distinguished from stridor by its pitch. Stertor is low-pitched, and can occur when breathing in, out or both. Stertor and stridor can occur together, such as when adenotonsillar hypertrophy and laryngomalacia occur together.