NCI Dictionary of Cancer Terms
The NCI Dictionary of Cancer Terms features 7,881 terms related to cancer and medicine.
Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.
- listen (flem)
- A more than normal amount of thick mucus made by the cells lining the upper airways and lungs. A buildup of phlegm may be caused by infection, irritation, or chronic lung disease, and can cause discomfort in the chest and coughing.