The crossword solution for the term 'whistling sound' is 'stridor, ' which is a high-pitched, wheezing sound that is caused by an obstruction in the airway. It is often associated with respiratory illnesses such as asthma and bronchitis. Stridor can also be caused by a foreign object lodged in the throat or windpipe. In some cases, stridor can be a sign of a more serious medical condition, such as a tumor or an infection.