Daniel Mark Lewin (Hebrew: ????? "???" ???? ?????; May 14, 1970 – September 11, 2001), sometimes spelled Levin, was an American–Israeli mathematician and entrepreneur who co-founded internet company Akamai Technologies.
A passenger onboard American Airlines Flight 11, it is believed that Lewin was stabbed by one of the hijackers of that flight, and was the first person murdered during the course of the attacks.