A few key components make trail running shoes different than your regular road running shoes.
The biggest difference between your trail shoes and your road shoes is the outsole. Some shoe designers use different rubber compounds that offer more slip resistance for crossing wet rocks or smooth roots.
Most trail running shoes also make use of deep rubber lugs on the outsole, which help grip loose dirt or mud. Usually, those lugs are multidirectional, giving you traction when you’re running uphill or downhill.
Some shoes have a dedicated rock plate—a thin piece of plastic or other material sandwiched into the midsole—which adds some stiffness and extra protection if you happen to step on a jagged rock.