in half

English

(set phrase) Into two halves.
- 1838 March – 1839 October, Charles Dickens, chapter 29, in The Life and Adventures of Nicholas Nickleby, London: Chapman and Hall, […], published 1839, →OCLC:
  Nicholas picked up Mr Lenville's ash stick which had flown out of his hand, and breaking it in half, threw him the pieces.
- 1905, P. G. Wodehouse, A Corner in Lines:
  "Kindly take them in batches of ten sheets, and tear them in half, Dunstable."
- 2014 July 2, Adam Withnall, “Hero Good Samaritan bends car door in half”, in The Independent, UK, retrieved 23 July 2014:
  A hero exhibiting “superhuman strength” has saved the life of a motorist trapped in a burning vehicle by bending the car's door in half with his bare hands.
(set phrase) By a divisor of two; to a numerical value which is half of the original value.
- 2005 April 26, Andrew Pollack, “Breast Cancer Recurrence Is Cut in Half by a Drug”, in New York Times, retrieved 23 July 2014:
  A biotechnology cancer drug cuts in half the risk that one type of breast cancer will recur after surgery.
- 2012 May 16, John Otis, “The Blast in Bogotá: A Reminder of Colombia's Unsolved Problems”, in Time, retrieved 23 July 2014:
  [H]e helped oversee a military offensive that cut the numbers of rebel forces in half to about 8,000 fighters.

Formerly proscribed as improper, e.g., by Webster 1913.

fifty-fifty — see fifty-fifty