what is overwatch mean?
In modern warfare, overwatch is a force protection tactic: the state of one small unit or military vehicle supporting another unit, while they are executing fire and movement tactics. An overwatching, or supporting unit has taken a position where it can observe the terrain ahead, especially likely enemy positions.
Overwatch is an upcoming multiplayer first-person shooter in development by Blizzard Entertainment. Unveiled on November 7, 2014 at BlizzCon, the game emphasizes cooperative gameplay using a cast of various heroes, each with their own abilities and roles within a team. The game is scheduled to enter a closed beta phase starting in North America from October 27, 2015.