A ripcord is the string you pull so a parachute opens. When you jump from a plane, the pack on your back stays shut until you pull that cord; then the cloth flies out and fills with air. People who jump for sport, and soldiers, use the word as ordinary shop talk. You will also hear it in films. Though actually, people stretch it: to pull the ripcord can mean to get out of a job, a plan, or a relationship fast — as if you were leaving a fall and opening a way to land. That picture still comes from the parachute, not from a second word. It is a plain, physical word, and a little like a film when people use the stretch.