The term 'Jets or Mets' refers to two professional sports teams in the United States. The New York Jets are a professional American football TEAM based in East Rutherford, New Jersey, and compete in the National Football League (NFL). The New York Mets are a professional baseball TEAM based in Queens, New York, and compete in Major League Baseball (MLB). The answer to the crossword puzzle is TEAM, which is an acronym for the four letters that make up the names of both teams.