Horde
Horde is a large number of zombies within the same block, or a zombie group organized using metagaming. The former group may consist of feral zombies, one or multiple zombie groups or a mix of both organized and unorganized zombies.
The inter-changable use of horde comes from the fact survivors can not distinguish a collection of feral zombies from an organized zombie group other than through recognizing the use of zombie group battle cries and the effectiveness of breaching defenses exhibited by metagaming horde.
Feeding Groan has blurred the line between feral hordes and organized zombies, because even ferals can gather effectively to assault a building after a breach.
The slang for zombie hordes that use metagaming to organize is Hive mind.
