A turtle is a battleground situation where a game is stalled for longer than the standard elapsed time. They mostly common occur in Warsong Gulch and Alterac Valley because of the circumstances given to where the game can be deadlocked intentionally or not. It is less likely to happen in Arathi Basin and Eye of the Storm because both games are based on points accumulated over time and have no purpose or method to stall intentionally.
Warsong Gulch can become a turtle game when both teams are at a standstill and cannot capture each other's flag. Example: Both teams have the opposing flag, but the flag cannot be captured until the other one is returned. Both teams have a strong defense, and any initiative for an offensive strike fails to retrieve the flag to its home base. However, some premade groups have been known to purposefully stall a Warsong Gulch battlegrounds in order to honor farm and camp the opposing team merely for honorable kills. Warsong Gulch turtles in the worst cases tend to go for hours.
Alterac Valley becomes a turtle when both teams cannot rush the other's defenses quickly enough to make it to the enemy general. A standard Alterac Valley game when ran quickly lasts from 12-15 minutes. Some games if stalled a little but one-sided go from 20-24 minutes. In the really bad situations, an Alterac Valley turtle will last up to 50 minutes. Intentionally causing a turtle in this battlegrounds is for the same reason, honor farming. Turtles here don't last as long as Warsong Gulch because for every kill, the opposing team's reinforcements gets decremented. Defeating the enemy captain and capturing all four towers also brings down the number of reinforcements leaving only the players to farm until the count reaches 0.