Room which you sit in, in the evenings?
I call mine my lounge but my kids call it a living room. My parents call theirs their sitting room and my my sister calls her's her "front room".
Lounge (but we live in a modern semi with an open plan lounge/diner) In my childhood we lived in a very large terraced house so had the front room (or best room) which was only used for high days and holidays when the open fire was lit - great occasion! We also had the living room and a scullery and a breakfast room. Its just the words which have changed over the years.