inflammation of the mucous membranes in one of the airways or cavities of the body

Catarrh (pronounced /kəˈtɑ:(r)/) is a thick fluid of mucus and white blood cells caused by the swelling of the mucous membranes in the head because of an infection. It is a symptom usually from the common cold and coughs, but can also be found in people with infections of the adenoids, middle ear, sinus or tonsils.