Repop

The term repop (short for repopulate) refers to when objects, areas, or mobs reset or respawn.

Area repop
Refers to when a whole area is repopulated.

Night and Day
Some repops only happen during in the day/night time period.

Instances
Instances only repop once the player or group has left the area. While the player or group stays in the area the mobs, keys etc will never repopulate.

Repop times
Repop times for areas vary.

instant repop
It is possible to kill a mob only to see it respawn again instantly.