From Proto-Indo-European *(p)st(e)rnu- (“to sneeze”), presumably with imitative deformation; the internal *-r- in the Latin word and its presumed cognates makes the word unlikely to be independently formed in all the branches it is found in. Cognate with Welsh trew (“sneeze”), Breton strevial, Ancient Greek πταρμός (ptarmós, “sneeze”), and Armenian փռշտալ (pʻṙštal, “to sneeze”). Also compare other onomatopoeic formations like Polish kichać, Russian чихать (čixatʹ), Lithuanian čiáudėti, and Sanskrit क्षु (kṣu).