croup: an infection of the upper airway, which obstructs breathing and causes a characteristic barking cough.The cough and other signs and symptoms of croup are the result of swelling around the voice box (larynx), windpipe (trachea) and bronchial tubes (bronchi). When a cough forces air through this narrowed passageway, the swollen vocal cords produce a noise similar to a seal barking. Likewise, taking a breath often produces a high-pitched whistling sound (stridor).
