A living room is a room in a home that's used for entertaining friends, talking, reading, or watching television. If you're a couch potato, you most likely spend lots of time in your living room.
You can also call a living room a lounge, a sitting room, a front room, or a parlor. It's distinguished from other rooms in a house by what it's used for. There's the dining room for eating, the kitchen for cooking, and the bedroom for sleeping. The living room, on the other hand, is for relaxing. It's an early 20th century invention, an offshoot of the old-fashioned formal parlor.