From old blues songs, particularly the Chicago style; a reference to the location in the slaughterhouse where the stock was killed and then butchered, hence a scene of danger, difficulty, bloodshed, etc.

A pick me is a woman that is willing to do anything for male approval. She will embarrass or throw other women under the bus to achieve this goal. The unfortunate thing about a pick me is usually the men they are trying to seek approval from are of poor quality and treat women badly, leaving little real benefit for the pick me.

Horror/Action game developed by Tripwire Interactive.

A coop game for 6 players to kill every zombie in plain sight of your gun

The bed(most commonly) or anywhere that can be used to have sex or "kill" the pussy(or dick).(ie, couch, shower, car, etc.); The bedroom.

Reference in certain blues and rock songs. Exact meaning unknown. Now meant to refer to school playgrounds where social heirarchies and roles are exercised and determined. May also refer to urban schools where firearms and violence are common.

There's 3 definitions of a killing floor :

1) When you stab the floor or shoot it with a gun, you're killing it, hence the "Killing Floor"
2) You're walking, you're happy and all, then the floor kills you, maybe because of some traps hidden in the floor, hance the "Killing Floor"
3) A video game about zombies, there's a lot of blood on the floor and slaughtering corpses, so it's a "killing floor".

Now you know.