Real Dictionary

cough
verb: When you cough, you force air out of your throat with a sudden, harsh noise. You often cough when you are ill, or when you are nervous or want to attract someone's attention.

cough in American English
the act or sound of coughing
to expel air suddenly and noisily from the lungs through the glottis, either as the result of an involuntary muscular spasm in the throat or to clear the air passages
intransitive verb: to expel air from the lungs suddenly with a harsh noise, often involuntarily
transitive verb: to expel by coughing

cough in British English
noun: an act, instance, or sound of coughing
verb: to expel air or solid matter from the lungs abruptly and explosively through the partially closed vocal chords