split second

split second (plural split seconds)

1. Alternative form of split-second.
   • 1912, G[ilbert] K[eith] Chesterton, “The Eye of Death; or, The Murder Charge”, in Manalive, New York, N.Y.: John Lane, →OCLC, part II (The Explanations of Innocent Smith), page 182:

     It's very dangerous, though, when a man thinks for a split second that he understands death.