COUGH, noun A violent effort of the lungs to throw off offending matter; a violent, sometimes involuntary, and sonorous expiration, suddenly expelling the air through the glottis. The convulsion of the muscles serving for exspiration gives great force to the air, while the contraction of the glottis produces the sound. The air forced violently carries along with it the phlegm or irritating matter which causes the convulsion or effort of the muscles.
COUGH, verb intransitive To have the lungs convulsed; to make a violent effort with noise to expel the air from the lungs, and evacuate any offending matter that irritates the parts or renders respiration difficult.
COUGH, verb transitive To expel from the lungs by a convulsive effort with noise; to expectorate; followed by up; as, to cough up phlegm.