The term 'defensive lines' refers to a group of players in American football who line up on the line of scrimmage and are responsible for defending against the opposing team's offensive line. The crossword solution for this term is 'cordons', which refers to a line of people or things arranged in a circle or ring around an area, often for protection or security. This term is used to describe the defensive lines in American football, as they form a protective barrier around the quarterback and other offensive players.