Parallel. There are several reasons. Some are more technical, but the simplest reason is: If they were in series and somebody turned off the TV, all the lights in the house would go out, along with the air conditioner and the toaster.
In series, nothing can be running unless EVERYTHING is running. If one thing is unplugged or turned off, then EVERYTHING goes off.
If the house was wired in series, then every outlet would need something plugged into it AND turned on, otherwise you couldn't have a light in your bedroom. Pretty inconvenient !
