Sea Change Meaning

(idiomatic) A profound transformation.

Example:   Public opinion has undergone a sea change since the 2002 elections.
c.1610-1611, William Shakespeare, The Tempest, Act 1, Scene 2,
  Full fathom five thy father lies: / Of his bones are coral made: / Those are pearls that were his eyes: / Nothing of him that doth fade / But doth suffer a sea-change / Into something rich and strange.
1910, Jack London, Theft: A Play In Four Acts, Actors' Description of Characters,
  Anthony Starkweather. […] Essentially a moral man, his rigid New England morality has suffered a sea change and developed into the morality of the master-man of affairs, equally rigid, equally uncompromising, but essentially Jesuitical in that he believes in doing wrong that right may come of it.