Bronchial is an adjective for the bronchial tubes: the air pipes that branch off from your windpipe and carry air down into the lungs, splitting again and again like a tree. If something is bronchial, it affects those tubes, or belongs to them. Doctors talk about a bronchial infection, bronchial asthma, or the bronchial tubes themselves. Everyday English often just says chest or lungs; bronchial is the more precise, slightly medical word. It does not name an illness on its own. Though actually, people stretch it: a bronchial cough may just mean a deep, chesty cough, even before anyone has looked at the tubes. It is not the same as a sore throat, which sits higher up.