Triple Kill
From Halopedia, the Halo wiki
Summary
Triple Kill Medal
http://img279.echo.cx/img279/4121/triplekill7ui.jpg
The Triple Kill Medal is awarded for killing 3 opponents within 4 seconds of each other. It is availible in all Multiplayer gametypes and has a Bungie difficulty rating of 6 (out of 10). It is represented by a steel medal with 3 stars.