A thick, viscous substance secreted by the mucous membranes of the respiratory passages, especially when produced in excessive or abnormal quantities.

The doctor advised him to drink plenty of fluids to help clear the phlegm from his throat.

Calmness of temperament; composure.

Despite the chaos around him, he maintained his phlegm and continued with his work.

In ancient and medieval physiology, one of the four bodily humours, thought to cause sluggishness when present in excess.

Galen believed that an imbalance of phlegm could make a person slow and apathetic.