Chain stun:

Chain stun is the repeated locking down of a hero by one disable after another, leaving little or no time to move, cast spells, or use items. In Dota 2, teams use chain stun to keep an enemy controlled long enough to secure a kill or prevent a key spell from being cast.

The term usually refers to coordinated stuns, roots, hexes, and other disables timed so their effects overlap or follow each other cleanly. Good spell timing and focus fire are important for chain stunning, especially against high-priority targets.

Related: Stun, Disable, Silence