One Flesh Meaning

(idiomatic) Two people united by marriage.

Example: 1840, James Fenimore Cooper, The Pathfinder, ch. 15:
  "This is reasonable and natural," returned Pathfinder; ". . . A woman would be likely to follow the man to whom she had plighted faith, and husband and wife are one flesh."
1875, Lord Alfred Tennyson, Queen Mary: A Drama, Act V:
  Mary: Have not I been the fast friend of your life
  Since mine began, and it was thought we two
  Might make one flesh, and cleave unto each other
  As man and wife?
1911, John Galsworthy, "A Christian" in Inn of Tranquility:
  We know Christ's saying of the married that they are one flesh!