Root / Ensnare:

Root, sometimes called ensnare, is a disable that prevents a unit from moving but usually still allows it to attack, cast spells, or use items. In Dota 2, rooting is commonly used to stop enemies from escaping, chasing, or repositioning without fully stunning them.

Roots are important because they can pin down mobile heroes while leaving them able to fight back, making them different from stuns and slows. Some abilities and items specifically apply a root or ensnare effect as part of their control toolkit.

Related: Stun, Slow, Disable, Silence