1. In computer networking, a stack is a frequently used method of describing TCP/IP.
2. In computer programming, a stack is a special data structure that removes items in the reverse order from that they are added.
3. A stack may also refer to a collection of computers that are stacked upon each other. This may also refer to a stack of computer motherboards and required components for a functional computer with no case that are used for a computer farm.
4. In some video games, multiple players join to defeat a creature, creating a party or raid. When fighting some creatures, it is necessary to stack together. When players stack, they are moving to a common spot, standing in a tight group to create a smaller target for the creature to hit or to share damage that is dealt by the creature, reducing the chance of any one player dying during the battle.