Phlegm (noun)

A thick, sticky mucus that is produced in the respiratory system and expelled through the mouth or nose.

Origin:

From the old french fleume, from the latin phlegma, from the greek φλέγμα (phlegma) meaning "inflammation".

Examples:

1. Phlegm is a common symptom of a cold or flu.
2. He coughed up a lot of phlegm this morning.
3. Phlegm can be clear, yellow, or green in color.
4. Excessive phlegm production can cause difficulty breathing.
5. Phlegm can be removed by coughing or by using a device called a mucus extractor.