Hiccup is a type of force breathing which occurs due to sudden spasm in our chest and throat muscles.Due to sudden shut down of glottis while eating or laughing continuously or due to any other reasons, flow of air for breathing gets cut off and the 'hic' sound comes.There are several reasons for causing hiccups.It is a kind of malfunction of nerves that control the movement of glottis and other muscle linked to breathing.