from latin desmos (controlled) and dromos (movement) is a mechanical solution for engine valvetrain movement that does not involve springs for opening and closing valves relying on rocker arms instead thus preventing "valve float". Ducati motorcycles are known for using desmodromic valve actuations on their engines.
"Forget about japanese crotch-rockets, desmodromic is the way to go!"
"Hey, look at that poser on the italian bike. Guess he's never heard of desmodromic actuation. He looks cool, though"