A spasm of the diaphragm, or the resulting sound.

“There was a loud hiccup from the back of the room and the class erupted in laughter.”

(by extension) Any spasm or sudden change.

A minor setback.

“There's been a slight hiccup in the processing of this quarter's results.”

To produce a hiccup; have the hiccups.

To say with a hiccup.

“"I haven't touched a drop, officer," the suspect hiccupped.”

To produce an abortive sound like a hiccup.

“The car engine hiccupped but wouldn't start.”