respiratory tractnoun [ C usually singular ]
/rɪˈspɪr.ə.tər.i ˌtrækt//ˈres.pɚ.ə.tɔːr.i ˌtrækt/specializedthe parts of the body that air passes through during the act of breathing, consisting of the mouth, nose, throat, and lungs:
upper respiratory tract infections such as the common cold
lower respiratory tract infections such as pneumonia