Complex sentence: As a description of U.S. foreign policy, the word originated in a report Kennan submitted to U.S. Defense Secretary James Forrestal in 1947, a report that was later used in a magazine article.
Split into simpler sentences: As a description of U.S. foreign policy, the word originated in a report Kennan submitted to U.S. Defense Secretary James Forrestal in 1947. It was a report that was later used in a magazine article.