A hiccup is an involuntary contraction (myoclonic jerk) of the diaphragm that may repeat several times per minute. In medicine, it is known as synchronous diaphragmatic flutter (SDF), or singultus, Latin for the act of catching one's breath while sobbing. The hiccup is an involuntary action involving a reflex arc. Once triggered, the reflex causes a strong contraction of the diaphragm followed about 0.25 second later by closure of the vocal cords, which results in the classic "hic" sound.
Hiccups may occur individually, or they may occur in bouts. The rhythm of the hiccup, or the time between hiccups, tends to be relatively constant.
A bout of hiccups, in general, resolves itself without intervention, although many home remedies are often used to attempt to shorten the duration. Medical treatment is occasionally necessary in cases of chronic hiccups.