What is the X in X-mas?
1570s, hickop, earlier hicket, hyckock, "a word meant to imitate the sound produced by the convulsion of the diaphragm" [Abram Smythe Farmer, "Folk-Etymology," London, 1882]. Cf. French hoquet, Danish hikke, etc. Modern spelling first recorded 1788; An Old English word for it was ælfsogoða, so called because hiccups were thought to be caused by elves.
1580s; see hiccup (n.).
hiccup hic·cup or hic·cough (hĭk'əp)
A spasm of the diaphragm causing sudden inhalation interrupted by spasmodic closure of the glottis, producing a characteristic noise.
A brief interruption; spasmodic stoppage: The violence in Moscow is another hiccup in Russia's drive for democracy (1980s+)