Nitinol is an alloy of nickel and titanium. It was discovered at the US Naval Ordnance Laboratory, and its name is a combination of where it was discovered and what it is made of: NIckel TItanium Naval Ordnance Laboratory
Researcher William Buehler was trying to make a better missile nose cone in 1959 and found that an alloy of equal part nickel and titanium worked well. He showed a folded-up piece to his colleagues. One heated it up with his lighter, and to everyone's surprise it resumed its previous shape.